Patent Application
20120189658
The present invention relates to virus-like particles. More specifically, the present invention is directed to virus-like particles comprising chimeric influenza hemagglutinin, and methods of producing chimeric influenza virus-like particles.
Influenza is the leading cause of death in humans due to a respiratory virus, and during “flu season”, it is estimated that 10-20% of the population worldwide may be infected, leading to 250-500,000 deaths annually.
The current method of combating influenza in humans is by annual vaccination. The vaccine is usually a combination of several strains that are predicted to be the dominant strains for the coming flu-season, however the number of vaccine doses produced annually is not sufficient to vaccinate the world's population. For example, Canada and the United-States obtain enough vaccine doses to immunize about one third of their population, and in Europe, only about 17% can be vaccinated given current production—in the face of a worldwide flu pandemic, this production would be insufficient. Even if the necessary annual production could somehow be met in a given year, the dominant strains change from year to year, thus stockpiling at low-need times in the year is not practical. Economical, large scale production of an effective influenza vaccine is of significant interest to government and private industry alike.
Influenza haemagglutinin (HA) surface glycoprotein is both a receptor-binding and membrane fusion protein. It is a trimer of identical subunits, each containing two disulphide-linked polypeptides, HA1 and HA2, that are derived by proteolytic cleavage of a precursor, HA0, that has a signal peptide sequence at its N-terminus and a membrane anchor sequence at its C-terminus Cleavage to form HA1 and HA2 generates the N-terminus of the smaller polypeptide, HA2, which has the membrane anchor sequence at its C-terminus. Cleavage is required for membrane fusion activity but not for immunogenicity. The HA2 N-terminal sequence is called the ‘fusion peptide’ because cleavage at similar hydrophobic sequences is also required for the activity of other virus fusion proteins, and because 20-residue synthetic peptide analogues of the sequence fuse membranes in vitro.
Generally, the surface of the globular ‘head’ comprises several flexible loops with well-characterized and variable antigenic regions designated as sites A, B, C, D and E (reviewed in Wiley et al., 1987. Annu. Rev Biochem 56:365-394). Insertion or replacement of short peptide sequences at some sites (e.g. B and E) for immunity studies have been described (Garcia-Sastré et al. 1995. Biologicals 23:171-178). Epidermal growth factor (EGF), single chain antibody (scFV) and the Fc domain of an IgG, ranging in size from 53 to 246 amino acids, have been inserted at the N-terminal end of a H7 and chimeras has been successfully expressed (Hatziioannou et al., 1999. Human Gene Therapy 10:1533-1544). More recently, 90 and 140 amino acid domains of Bacillus anthracis protective antigen have been fused to the amino terminus of a H3 (Li et al., 2005. J. Virol 79:10003-1002). Copeland (Copeland et al., 2005. J. Virol 79:6459-6471) describes the expression of the gp120 Env HIV surface glycoprotein on a H3 stalk, where the gp120 domain replaced the whole globular head of HA.
Several recombinant products have been developed as recombinant influenza vaccine candidates. These approaches have focused on the expression, production, and purification of influenza type A HA and NA proteins, including expression of these proteins using baculovirus infected insect cells (Crawford et al, 1999 Vaccine 17:2265-74; Johansson, 1999 Vaccine 17:2073-80), viral vectors, and DNA vaccine constructs (Olsen et al., 1997 Vaccine 15:1149-56).
Production of a non-infectious influenza virus strain for vaccine purposes is one way to avoid inadvertent infection. Alternatively, virus-like particles (VLPs) as substitutes for the cultured virus have been investigated. VLPs mimic the structure of the viral capsid, but lack a genome, and thus cannot replicate or provide a means for a secondary infection. Current influenza VLP production technologies rely on the co-expression of multiple viral proteins, and this dependence represents a drawback of these technologies since in case of a pandemic and of yearly epidemics, response time is crucial for vaccination. A simpler VLP production system, for example, one that relies on the expression of only one or a few viral proteins without requiring expression of non-structural viral proteins is desirable to accelerate the development of vaccines.
Enveloped viruses may obtain their lipid envelope when ‘budding’ out of the infected cell and obtain the membrane from the plasma membrane, or from that of an internal organelle. In mammalian or baculovirus cell systems, for example, influenza buds from the plasma membrane (Quan et al 2007 J. Virol 81:3514-3524). Only a few enveloped viruses are known to infect plants (for example, members of the Tospoviruses and Rhabdoviruses). Of the known plant enveloped viruses, they are characterized by budding from internal membranes of the host cell, and not from the plasma membrane. Although a small number of recombinant VLPs have been produced in plant hosts, none were derived from the plasma membrane, raising the question whether plasma membrane-derived VLPs, including influenza VLPs can be produced in plants.
Formation of VLPs, in any system, places considerable demands on the structure of the proteins—altering short stretches of sequence that correspond to selected surface loops of a globular structure may not have much of an effect on expression of the polypeptide itself, however structural studies are lacking to demonstrate the effect of such alterations on the formation of VLPs. The cooperation of the various regions and structures of HA (e.g. the membrane anchor sequences, the stalk or stem regions of the trimer that separate the globular head from the membranes) has evolved with the virus and may not be amendable to similar alterations without loss of HA trimer integrity and VLP formation.
The production of influenza HA VLPs has been previously described by the inventors in WO 2009/009876.
The present invention relates to virus-like particles. More specifically, the present invention is directed to virus-like particles comprising chimeric influenza hemagglutinin, and methods of producing chimeric influenza hemagglutinin virus-like particles.
It is an object of the invention to provide an improved chimeric influenza virus-like particle (VLP).
The present invention provides a polypeptide comprising a chimeric influenza HA comprising a stem domain cluster (SDC), a head domain cluster (HDC) and a transmembrane domain cluster (TDC) wherein: the SDC comprises an F′1, F′2 and F subdomain; the HDC comprises an RB, E1 and E2 subdomain; the TDC comprises a TmD and Ctail subdomain; and wherein at least one subdomain is of a first influenza HA and the other subdomains are of one or more second influenza HA. The first and second influenza HA may independently be selected from the group comprising H1, H3, H5 and B. Furthermore, the polypeptide may comprise a signal peptide.
The present invention also provides a nucleic acid encoding the polypeptide comprising a chimeric influenza HA comprising a stem domain cluster (SDC), a head domain cluster (HDC) and a transmembrane domain cluster (TDC) wherein: the SDC comprises an F′1, F′2 and F subdomain; the HDC comprises an RB, E1 and E2 subdomain; the TDC comprises a TmD and Ctail subdomain; and wherein at least one subdomain is of a first influenza HA, and the other subdomains are of one or more second influenza HA. The nucleic acid may also encode the polypeptide that comprises a signal peptide in addition to the SDC, HDC and TDC as defined.
A method of producing chimeric influenza virus like particles (VLPs) in a plant is also provided, the method comprising:
a) introducing a nucleic acid encoding a chimeric influenza HA comprising a signal peptide, a stem domain cluster (SDC), a head domain cluster (HDC) and a transmembrane domain cluster (TDC) wherein: the SDC comprises an F′1, F′2 and F subdomain; the HDC comprises an RB, E1 and E2 subdomain; the TDC comprises a TmD and Ctail subdomain; and wherein at least one subdomain is of a first influenza HA, and the other subdomains are of one or more second influenza HA into the plant, or portion thereof, and
b) incubating the plant, or portion thereof, under conditions that permit the expression of the nucleic acid, thereby producing the VLPs.
The present invention includes the method described above wherein in the step of introducing (step a), the nucleic acid is introduced in the plant in a transient manner. Alternatively, in the step of introducing (step a), the nucleic acid is introduced in the plant and is stably integrated. The method may further comprise a step of c) harvesting the host and purifying the VLPs.
The present invention provides a plant, or portion thereof, comprising a chimeric influenza HA, or a nucleotide sequence encoding the chimeric influenza HA, the chimeric influenza HA comprising a stem domain cluster (SDC), a head domain cluster (HDC) and a transmembrane domain cluster (TDC) wherein: the SDC comprises an F′1, F′2 and F subdomain; the HDC comprises an RB, E1 and E2 subdomain; the TDC comprises a TmD and Ctail subdomain; and wherein at least one subdomain is of a first influenza HA and the other subdomains are of one or more second influenza HA.
The plant, or portion thereof, may further comprise a nucleic acid comprising a nucleotide sequence encoding one or more than one chaperone protein operatively linked to a regulatory region active in a plant. The one or more than one chaperon proteins may be selected from the group comprising Hsp40 and Hsp70.
The present invention pertains to a virus like particle (VLP) comprising a chimeric influenza HA, the chimeric influenza HA comprising a stem domain cluster (SDC), a head domain cluster (HDC) and a transmembrane domain cluster (TDC) wherein: the SDC comprises an F′1, F′2 and F subdomain; the HDC comprises an RB, E1 and E2 subdomain; the TDC comprises a TmD and Ctail subdomain; and wherein at least one subdomain is of a first influenza HA and the other subdomains are of one or more second influenza HA. The VLP may further comprise plant-specific N-glycans, or modified N-glycans.
A composition comprising an effective dose of the VLP as just described and a pharmaceutically acceptable carrier is also provided.
In an alternate aspect of the present invention there is provided a method of inducing immunity to an influenza virus infection in a subject, comprising administering the VLP to the subject. The VLP may administered to a subject orally, intradermally, intranasally, intramusclarly, intraperitoneally, intravenously, or subcutaneously.
Regulatory regions that may be operatively linked to a sequence encoding a chimeric HA protein include those that are operative in a plant cell, an insect cell or a yeast cell. Such regulatory regions may include a plastocyanin regulatory region, a regulatory region of Ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO), chlorophyll a/b binding protein (CAB) or ST-LS 1. Other regulatory regions include a 5′ UTR, 3′ UTR or terminator sequences. The plastocyanin regulatory region may be an alfalfa plastocyanin regulatory region; the 5′ UTR, 3′UTR or terminator sequences may also be alfalfa sequences.
The present invention provides a chimeric influenza HA polypeptide comprised of a first influenza and a second influenza, the first influenza and the second influenza may be independently selected from the group comprising B, H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15 and H16; with the proviso that the first influenza and the second influenza are not the same influenza type, subtype, or of the same origin.
In accordance with some aspects of the invention, the chimeric influenza HA polypeptide comprises a signal peptide sequence, the signal peptide sequence may be selected from the group comprising a native signal peptide sequence, an alfalfa PDI signal peptide sequence, an influenza H5 signal peptide sequence and an influenza H1 signal peptide sequence
The present invention provides a method for producing a VLP containing chimeric influenza hemagglutinin (HA) within a host capable of producing a VLP, including a plant, insect, or yeast comprising, introducing a nucleic acid encoding a chimeric influenza HA comprising a stem domain cluster (SDC), a head domain cluster (HDC) and a transmembrane domain cluster (TDC) wherein: the SDC comprises an F′1, F′2 and F subdomain; the HDC comprises an RB, E1 and E2 subdomain; the TDC comprises a TmD and Ctail subdomain; and wherein at least one subdomain is of a first influenza HA and the other subdomains are of one or more second influenza HA, into the host, and incubating the host under conditions that permit the expression of the nucleic acid, thereby producing the VLPs.
The production of VLPs in plants presents several advantages over the production of these particles in insect cell culture. Plant lipids can stimulate specific immune cells and enhance the immune response induced. Plant membranes are made of lipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), and also contain glycosphingolipids that are unique to plants and some bacteria and protozoa. Sphingolipids are unusual in that they are not esters of glycerol like PC or PE but rather consist of a long chain amino alcohol that forms an amide linkage to a fatty acid chain containing more than 18 carbons. PC and PE as well as glycosphingolipids can bind to CD1 molecules expressed by mammalian immune cells such as antigen-presenting cells (APCs) like dentritic cells and macrophages and other cells including B and T lymphocytes in the thymus and liver. Furthermore, in addition to the potential adjuvant effect of the presence of plant lipids, the ability of plant N-glycans to facilitate the capture of glycoprotein antigens by antigen presenting cells, may be advantageous of the production of chimeric VLPs in plants. Without wishing to be bound by theory, it is anticipated that plant-made chimeric VLPs induce a stronger immune reaction than chimeric VLPs made in other manufacturing systems and that the immune reaction induced by these plant-made chimeric VLPs is stronger when compared to the immune reaction induced by live or attenuated whole virus vaccines.
Contrary to vaccines made of whole viruses, chimeric VLPs provide the advantage as they are non-infectious, thus restrictive biological containment is not as significant an issue as it would be working with a whole, infectious virus, and is not required for production. Plant-made chimeric VLPs provide a further advantage again by allowing the expression system to be grown in a greenhouse or field, thus being significantly more economical and suitable for scale-up.
Additionally, plants do not comprise the enzymes involved in synthesizing and adding sialic acid residues to proteins. VLPs may be produced in the absence of neuraminidase (NA), and there is no need to co-express NA, or to treat the producing cells or extract with sialidase (neuraminidase), to ensure VLP production in plants
This summary of the invention does not necessarily describe all features of the invention of the invention.
These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings wherein:
The present invention relates to virus-like particles. More specifically, the present to invention is directed to virus-like particles comprising chimeric influenza hemagglutinin, and methods of producing chimeric influenza virus-like particles.
The following description is of a preferred embodiment.
The present invention provides a nucleic acid comprising a nucleotide sequence encoding a chimeric influenza hemagglutinin (HA) operatively linked to a regulatory region active in a plant.
Furthermore, the present invention provides a method of producing virus like particles (VLPs) in a plant. The method involves introducing a nucleic acid encoding a chimeric influenza HA operatively linked to a regulatory region active in the plant, into the plant, or portion of the plant, and incubating the plant or a portion of the plant under conditions that permit the expression of the nucleic acid, thereby producing the VLPs.
The present invention further provides for a VLP comprising a chimeric influenza HA. The VLP may be produced by the method as provided by the present invention.
By “chimeric protein” or “chimeric polypeptide”, it is meant a protein or polypeptide that comprises amino acid sequences from two or more than two sources, for example but not limited to, two or more influenza types or subtypes, or influenza's of a different origin, that are fused as a single polypeptide. The chimeric protein or polypeptide may include a signal peptide that is the same as, or heterologous with, the remainder of the polypeptide or protein. The chimeric protein or chimeric polypeptide may be produced as a transcript from a chimeric nucleotide sequence, and the chimeric protein or chimeric polypeptide cleaved following synthesis, and as required, associated to form a multimeric protein. Therefore, a chimeric protein or a chimeric polpypeptide also includes a protein or polypeptide comprising subunits that are associated via disulphide bridges (i.e. a multimeric protein). For example, a chimeric polpeptide comprising amino acid sequences from two or more than two sources may be processed into subunits, and the subunits associated via disulphide bridges to produce a chimeric protein or chimeric polypeptide (see
The chimeric influenza HA according to various embodiments of the present invention may comprise a stem domain complex (SDC) a head domain complex (HDC) and a transmembrane domain complex (TDC), where one or more than one subdomain of either the SDC, HDC or TDC is of a first influenza HA type, subtype or from one origin, and one or more than one subdomain of either the SDC, HDC or TDC is from a second influenza HA type, subtype, or from a second or different origin. As described herein, the “SDC” comprises an F′1, F′2 and F subdomain, the “HDC” comprises an RB, E1 and E2 subdomain, the “TDC” comprises a TmD and Ctail subdomain (TMD/CT; see
The term “virus like particle” (VLP), or “virus-like particles” or “VLPs” refers to structures that self-assemble and comprise structural proteins such as influenza HA protein, or chimeric influenza HA protein. VLPs and chimeric VLPs are generally morphologically and antigenically similar to virions produced in an infection, but lack genetic information sufficient to replicate and thus are non-infectious. VLPs and chimeric VLPs may be produced in suitable host cells including plant host cells. Following extraction from the host cell and upon isolation and further purification under suitable conditions, VLPs and chimeric VLPs may be purified as intact structures.
Chimeric VLPs, or VLPs, produced from influenza derived proteins, in accordance with the present invention do not comprise M1 protein. The M1 protein is known to bind RNA (Wakefield and Brownlee, 1989) which is a contaminant of VLP preparation. The presence of RNA is undesired when obtaining regulatory approval for the chimeric VLP product, therefore a chimeric VLP preparation lacking RNA may be advantageous.
The chimeric VLPs of the present invention may be produced in a host cell that is characterized by lacking the ability to sialylate proteins, for example a plant cell, an insect cell, fungi, and other organisms including sponge, coelenterara, annelida, arthoropoda, mollusca, nemathelminthea, trochelmintes, plathelminthes, chaetognatha, tentaculate, chlamydia, spirochetes, gram-positive bacteria, cyanobacteria, archaebacteria, or the like. See, for example Gupta et al., 1999. Nucleic Acids Research 27:370-372; Toukach et al., 2007. Nucleic Acids Research 35:D280-D286; Nakahara et al., 2008. Nucleic Acids Research 36:D368-D371. The chimeric VLPs produced as described herein do not typically comprise neuraminidase (NA). However, NA may be co-expressed with HA should VLPs comprising HA and NA be desired.
The invention also provides VLPs comprising chimeric HA that obtain a lipid envelope from the plasma membrane of the cell in which the chimeric HA are expressed. For example, if the chimeric HA is expressed in a plant-based system, the resulting VLP may obtain a lipid envelope from the plasma membrane of the plant cell.
Generally, the term “lipid” refers to a fat-soluble (lipophilic), naturally-occurring molecules. A chimeric VLP produced in a plant according to some aspects of the invention may be complexed with plant-derived lipids. The plant-derived lipids may be in the form of a lipid bilayer, and may further comprise an envelope surrounding the VLP. The plant derived lipids may comprise lipid components of the plasma membrane of the plant where the VLP is produced, including phospholipids, tri-, di- and monoglycerides, as well as fat-soluble sterol or metabolites comprising sterols. Examples include phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol, phosphatidylserine, glycosphingolipids, phytosterols or a combination thereof. A plant-derived lipid may alternately be referred to as a ‘plant lipid’. Examples of phytosterols include campesterol, stigmasterol, ergosterol, brassicasterol, delta-7-stigmasterol, delta-7-avenasterol, daunosterol, sitosterol, 24-methylcholesterol, cholesterol or beta-sitosterol—see, for example, Mongrand et al., 2004. As one of skill in the art would understand, the lipid composition of the plasma membrane of a cell may vary with the culture or growth conditions of the cell or organism, or species, from which the cell is obtained. Generally, beta-sitosterol is the most abundant phytosterol.
Cell membranes generally comprise lipid bilayers, as well as proteins for various functions. Localized concentrations of particular lipids may be found in the lipid bilayer, referred to as ‘lipid rafts’. These lipid raft microdomains may be enriched in sphingolipids and sterols. Without wishing to be bound by theory, lipid rafts may have significant roles in endo and exocytosis, entry or egress of viruses or other infectious agents, inter-cell signal transduction, interaction with other structural components of the cell or organism, such as intracellular and extracellular matrices.
The invention includes VLPs comprising chimeric HA, of which the subdomains may be obtained from any type, subtype of influenza virus which may infect humans, including, for example, B, H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15 and H16 types or subtypes. In some embodiments, the influenza virus may be of an H1, H3, H5 or B types or subtypes. Non limiting examples of H1, H3, H15 or B types or subtypes include the A/New Caledonia/20/99 subtype (H1N1) (“H1/NC”; SEQ ID NO:56), the H1 A/California 04/09 subtype (H1N1) (“H1/Cal”; SEQ ID NO:86), the A/Indonesia/5/05 sub-type (H5N1) (“H5/Indo”), A/Brisbane/59/2007 (“H1/Bri”), and B/Florida/4/2006 (“B/Flo”) and H3 A/Brisbane/10/2007 (“H3/Bri”). Furthermore, the chimeric HA may comprise one or more subdomains of a hemagglutinin that is isolated from one or more emerging or newly-identified influenza viruses.
The present invention also pertains to influenza viruses which infect other mammals or host animals, for example humans, primates, horses, pigs, birds, avian water fowl, migratory birds, quail, duck, geese, poultry, chicken, camel, canine, dogs, feline, cats, tiger, leopard, civet, mink, stone marten, ferrets, house pets, livestock, mice, rats, seal, whale and the like. Some influenza viruses may infect more than one host animal.
With reference to influenza virus, the term “hemagglutinin” or “HA” as used herein refers to a structural glycoprotein of influenza viral particles. The structure of influenza hemagglutinin is well-studied and demonstrates a high degree of conservation in secondary, tertiary and quaternary structure. This structural conservation is observed even though the amino acid sequence may vary (see, for example, Skehel and Wiley, 2000 Ann Rev Biochem 69:531-69; Vaccaro et al 2005; which is incorporated herein by reference). Nucleotide sequences encoding HA are well known, and are available for example, from the BioDefense and Public Health Database (for example at URL: biohealthbase.org/GSearch/home.do?decorator=influenza) or the databases maintained by the National Center for Biotechnology Information (NCBI; for example at URL: ncbi.nlm.nih.gov/sites/entrez?db=nuccore&cmd=search&term=influenza) both of which are incorporated herein by reference.
The HA monomer may be subdivided in three functional domains—a stem domain, or stem domain cluster (SDC), a globular head domain, or head domain cluster (HDC) and a transmembrane domain cluster (TDC). The SDC comprises four subdomains, a fusion peptide F, F′1 and F′2 (this subdomain may be generally referred to as a ‘backbone’). The TDC comprises two subdomains, the transmembrane (TmD) and a C terminal tail (CT). The HDC comprises three subdomains, vestigial esterase domains E1′ and E2, and a receptor binding domain RB. The SDC and HDC may be collectively referred to as the ‘ectodomain’. A publication by Ha et al. 2002 (EMBO J. 21:865-875; which is incorporated herein by reference) illustrates the relative orientation of the various subdomains of the SDC and HDC in several influenza subtypes, based on Xray crystallographic structures. A schematic diagram of the subdomains relative to N and C termini of the HA1 and HA2 polypeptides is shown in
Amino acid variation is tolerated in hemagglutinins of influenza viruses. This variation provides for new strains that are continually being identified. Infectivity between the new strains may vary. However, formation of hemagglutinin trimers, which subsequently form VLPs is maintained. The present invention, therefore, provides for a hemagglutinin amino acid sequence comprising chimeric HA, or a nucleic acid encoding a chimeric hemagglutinin amino acid sequence, that forms VLPs in a plant, and includes known sequences and variant HA sequences that may develop. The present invention also pertains to the use of a chimeric HA polypeptide comprising a TDC, SDC and HDC. For example the chimeric HA protein may be HA0, or a cleaved chimeric HA comprising subdomains of HA1 and HA2 from two or more influenza types. The chimeric HA protein may be used in the production or formation of VLPs using a plant, or plant cell, expression system.
HA0 may be expressed and folded to form a trimer, which may subsequently assemble into VLPs. Cleavage of HA0 yields HA1 and HA2 polypeptides linked by a disulfide bridge (see
The HA0 polypeptide comprises several domains. The RB subdomain of the HDC comprises several loops in antigenic regions designated as site A-E. Antibodies that may neutralize infectious influenza virus are frequently targeted to one or more of these sites. The vestigial esterase subdomains (E1 and E2) may have a role in fusion, and may bind Ca++. The F, F′1 and F′2 domains interact and cooperate to form a stem, raising the head of the HA trimer above the membrane. A TmD and CT may be involved in anchoring of the folded HA to a membrane. The TmD may have a role in affinity of HA for lipid rafts, while the CT may have a role in secretion of HA, while some of the cysteine residues found in the CT subdomain may be palmitoylated. A signal peptide (SP) may also be found at the N terminus of the HA0 polypeptide.
Processing of an N-terminal signal peptide (SP) sequence during expression and/or secretion of influenza hemagglutinins may have a role in the folding of the HA. The term “signal peptide” refers generally to a short (about 5-30 amino acids) sequence of amino acids, found generally at the N-terminus of a hemagglutinin polypeptide that may direct translocation of the newly-translated polypeptide to a particular organelle, or aid in positioning of specific domains of the polypeptide chain relative to others. The signal peptide of hemagglutinins target the translocation of the protein into the endoplasmic reticulum and have been proposed to aid in positioning of the N-terminus proximal domain relative to a membrane-anchor domain of the nascent hemagglutinin polypeptide to aid in cleavage and folding of the mature hemagglutinin.
Insertion of HA within the endoplasmic reticulum (ER) membrane of the host cell, signal peptide cleavage and protein glycosylation are co-translational events. Correct folding of HA requires glycosylation of the protein and formation of at least 6 intra-chain disulfide bonds (see
A signal peptide may be native to the hemagglutinin, or a signal peptide may be heterologous with respect to the primary sequence of hemagglutinin being expressed. A chimeric HA may comprise a signal peptide from a first influenza type, subtype or strain with the balance of the HA from one or more than one different influenza type, subtype or strain. For example the native SP of HA subtypes B H1, H2, H3, H5, H6, H7, H9 or influenza type B may be used to express the HA in a plant system. In some embodiments of the invention, the SP may be of an influenza type B, H1, H3 or H5; or of the subtype H1/Bri, H1/NC, H5/Indo, H3/Bri or B/Flo.
A SP may also be non-native, for example, from a structural protein or hemagglutinin of a virus other than influenza, or from a plant, animal or bacterial polypeptide. A non limiting example of a signal peptide that may be used is that of alfalfa protein disulfide isomerase (PDI SP; nucleotides 32-103 of Accession No. Z11499; SEQ ID NO: 34;
The present invention therefore provides for a chimeric influenza hemagglutinin comprising a native, or a non-native signal peptide, and nucleic acids encoding such chimeric hemagglutinins.
Correct folding of the hemagglutinins may be important for stability of the protein, formation of multimers, formation of VLPs and function of the HA (ability to hemagglutinate), among other characteristics of influenza hemagglutinins. Folding of a protein may be influenced by one or more factors, including, but not limited to, the sequence of the protein, the relative abundance of the protein, the degree of intracellular crowding, the availability of cofactors that may bind or be transiently associated with the folded, partially folded or unfolded protein, the presence of one or more chaperone proteins, or the like.
Heat shock proteins (Hsp) or stress proteins are examples of chaperone proteins, which may participate in various cellular processes including protein synthesis, intracellular trafficking, prevention of misfolding, prevention of protein aggregation, assembly and disassembly of protein complexes, protein folding, and protein disaggregation. Examples of such chaperone proteins include, but are not limited to, Hsp60, Hsp65, Hsp 70, Hsp90, Hsp100, Hsp20-30, Hsp10, Hsp100-200, Hsp100, Hsp90, Lon, TF55, FKBPs, cyclophilins, ClpP, GrpE, ubiquitin, calnexin, and protein disulfide isomerases (see, for example, Macario, A. J. L., Cold Spring Harbor Laboratory Res. 25:59-70. 1995; Parsell, D. A. & Lindquist, S. Ann. Rev. Genet. 27:437-496 (1993); U.S. Pat. No. 5,232,833). As described herein, chaperone proteins, for example but not limited to Hsp40 and Hsp70 may be used to ensure folding of a chimeric HA.
Examples of Hsp70 include Hsp72 and Hsc73 from mammalian cells, DnaK from bacteria, particularly mycobacteria such as Mycobacterium leprae, Mycobacterium tuberculosis, and Mycobacterium bovis (such as Bacille-Calmette Guerin: referred to herein as Hsp71). DnaK from Escherichia coli, yeast and other prokaryotes, and BiP and Grp78 from eukaryotes, such as A. thaliana (Lin et al. 2001 (Cell Stress and Chaperones 6:201-208). A particular example of an Hsp70 is A. thaliana Hsp70 (encoded by Genbank ref: AY120747.1). Hsp70 is capable of specifically binding ATP as well as unfolded polypeptides and peptides, thereby participating in protein folding and unfolding as well as in the assembly and disassembly of protein complexes.
Examples of Hsp40 include DnaJ from prokaryotes such as E. coli and mycobacteria and HSJ1, HDJ1 and Hsp40 from eukaryotes, such as alfalfa (Frugis et al., 1999. Plant Molecular Biology 40:397-408). A particular example of an Hsp40 is M. sativa MsJ1 (AJ000995.1 or SEQ ID NO: 76). Hsp40 plays a role as a molecular chaperone in protein folding, thermotolerance and DNA replication, among other cellular activities.
Among Hsps, Hsp70 and its co-chaperone, Hsp40, are involved in the stabilization of translating and newly synthesized polypeptides before the synthesis is complete. Without wishing to be bound by theory, Hsp40 binds to the hydrophobic patches of unfolded (nascent or newly transferred) polypeptides, thus facilitating the interaction of Hsp70-ATP complex with the polypeptide. ATP hydrolysis leads to the formation of a stable complex between the polypeptide, Hsp70 and ADP, and release of Hsp40. The association of Hsp70-ADP complex with the hydrophobic patches of the polypeptide prevents their interaction with other hydrophobic patches, preventing the incorrect folding and the formation of aggregates with other proteins (reviewed in Hartl, F U. 1996. Nature 381:571-579).
Native chaperone proteins may be able to facilitate correct folding of low levels of recombinant protein, but as the expression levels increase, the abundance of native chaperones may become a limiting factor. High levels of expression of hemagglutinin in the agroinfiltrated leaves may lead to the accumulation of hemagglutinin polypeptides in the cytosol, and co-expression of one or more than one chaperone proteins such as Hsp70, Hsp40 or both Hsp70 and Hsp40 may reduce the level of misfolded or aggregated hemagglutinin polypeptides, and increase the number of polypeptides exhibiting tertiary and quaternary structural characteristics that allow for hemagglutination and/or formation of virus-like particles. SEQ ID NO: 77 is a nucleic acid sequence of a portion of construct number R850, from HindIII (in the multiple cloning site, upstream of the promoter) to EcoRI (immediately downstream of the NOS terminator), encoding HSP40 (underlined). SEQ ID NO: 78 is a nucleic acid sequence of a portion of construct number R860, from HindIII (in the multiple cloning site, upstream of the promoter) to EcoRI (immediately downstream of the NOS terminator), encoding HSP70 (underlined). SEQ ID NO: 79 is a nucleic acid sequence of a portion of construct number R870, from HindIII (in the multiple cloning site, 5 upstream of the promoter) to EcoRI (immediately downstream of the NOS terminator) encoding HSP40 (underlined italic) and HSP70 (underlined).
Therefore, the present invention also provides for a method of producing chimeric influenza VLPs in a plant, wherein a first nucleic acid encoding a chimeric influenza HA is co-expressed with a second nucleic acid encoding a chaperone. The first and second nucleic acids may be introduced to the plant in the same step, or may be introduced to the plant sequentially.
VLPs may be assessed for structure and size by, for example, hemagglutination assay, electron microscopy, or by size exclusion chromatography.
For size exclusion chromatography, total soluble proteins may be extracted from plant tissue by homogenizing (Polytron) sample of frozen-crushed plant material in extraction buffer, and insoluble material removed by centrifugation. Precipitation with PEG may also be of benefit. The soluble protein is quantified, and the extract passed through a Sephacryl™ column. Blue Dextran 2000 may be used as a calibration standard. Following chromatography, fractions may be further analyzed by immunoblot to determine the protein complement of the fraction.
The present invention also provides for a plant comprising a nucleic acid encoding one, or more than one chimeric influenza hemagglutinin and a nucleic acid encoding one or more than one chaperones.
The present invention includes nucleotide sequences:
SEQ ID NO: 63 (construct 690; a chimeric H5/H1 expression cassette comprising alfalfa plastocyanin promoter and 5′ UTR, chimeric hemagglutinin coding sequence, alfalfa plastocyanin 3′ UTR and terminator sequences) and the underlined portion of SEQ ID NO:63 encoding SP, F1, E1 of H5/Indo-RB of H1/Bri-E2, F2, F, TMD/CT of H5/Indo;
SEQ ID NO: 64 (construct 691; a chimeric H5/H1 expression cassette comprising alfalfa plastocyanin promoter and 5′ UTR, chimeric hemagglutinin coding sequence, alfalfa plastocyanin 3′ UTR and terminator sequences), and the underlined portion of SEQ ID NO:64, encoding SP, F′1, of H5/Indo-E1, RB. E2 of H1/Bri-F′2, F, TMD/CT of H5/Indo;
SEQ ID NO: 65 (construct 696;a chimeric H1/H5 expression cassette comprising alfalfa plastocyanin promoter and 5′ UTR, chimeric hemagglutinin coding sequence, alfalfa plastocyanin 3′ UTR and terminator sequences)and the underlined portion of SEQ ID NO:65 encoding PDI SP-F′1, E1 of H1/NC-RB of H5/Indo-E2, F′2, F, TMD/CT of H1/NC;
SEQ ID NO: 68 (construct 733; the SpPDI H1/Bri expression cassette comprising the CaMV 35S promoter, CPMV-HT 5′ UTR, coding sequence of the signal peptide from PDI, hemagglutinin coding sequence of H1 form A/Brisbane/59/07 (H1N1), CPMV-HT 3′ UTR and NOS terminator sequences), and the underlined portion of SEQ ID NO:68, encoding PDI SP-F′1, E1, RB, E2, F′2, F, TMD/CT of H1/BRI;
SEQ ID NO: 69 (construct 734; a chimeric H5/H1 expression cassette comprising the CaMV 35S promoter, CPMV-HT 5′ UTR, chimeric hemagglutinin coding sequence, CPMV-HT 3′ UTR and NOS terminator sequences). The coding sequence of chimeric HA is underlined, encoding the same chimieric HA as SEQ ID NO:63;
SEQ ID NO: 71 (construct 736; an HA expression cassette comprising the CaMV 35S promoter, CPMV-HT 5′ UTR, coding sequence of the signal peptide from PDI, hemagglutinin coding sequence of H3 form A/Brisbane/10/07 (H2N3), CPMV-HT 3′ UTR and NOS terminator sequences), and the underlined portion of SEQ ID NO: 71 encoding PDI SP-F′1, E1, RB, E2, F2, F, TMD/CT of H3/Bri;
SEQ ID NO: 72 (construct 737; a chimeric H5/H3 expression cassette comprising the CaMV 35S promoter, CPMV-HT 5′ UTR, chimeric hemagglutinin coding sequence, CPMV-HT 3′ UTR and NOS terminator sequences), and the underlined portion of SEQ ID NO:72 encoding PDI SP-F′1, E1, RB, E2, F2, F, TMD/CT of H5/Indo;
SEQ ID NO: 74 (construct 739; an HA expression cassette comprising the CaMV 35S promoter, CPMV-HT 5′ UTR, coding sequence of the signal peptide from PDI, hemagglutinin coding sequence of HA form B/Florida/4/06, CPMV-HT 3′ UTR and NOS terminator sequences), and the underlined portion of SEQ ID NO:74 encoding PDI SP-F′1, E1, RB, E2, F′2, F, TMD/CT of B/Flo;
SEQ ID NO: 75 (construct 734; a chimeric H5/B expression cassette comprising the CaMV 35S promoter, CPMV-HT 5′ UTR, chimeric hemagglutinin coding sequence, CPMV-HT 3′ UTR and NOS terminator sequences), and the underlined portion of SEQ ID NO:75 encoding PDI SP-F′1, E1, RB, E2, F′2, F of B/Flo-TND/CT of H5/Indo.
The present invention also includes a nucleotide sequence that hybridizes under stringent hybridisation conditions to the underlined portions of any one of SEQ ID NOs:63-65, 68, 69, and 71-75. The present invention also includes a nucleotide sequence that hybridizes under stringent hybridisation conditions to a complement of the underlined portions of any one of SEQ ID NOs:63-65, 68, 69, and 71-75. These nucleotide sequences that hybridize to the underlined portions of SEQ ID NOs:63-65, 68, 69, and 71-75, or a complement of the underlined portions of SEQ ID NOs:63-65, 68, 69, and 71-75, encode a chimeric hemagglutinin protein that, when expressed forms a chimeric VLP, and the chimericVLP induces production of an antibody when administered to a subject. For example, expression of the nucleotide sequence within a plant cell forms a chimeric VLP, and the chimeric VLP may be used to produce an antibody that is capable of binding HA, including mature HA, HA0, HA1 or HA2 of one or more influenza types or subtypes. The chimeric VLP, when administered to a subject, induces an immune response.
Hybridization under stringent hybridization conditions is known in the art (see for example Current Protocols in Molecular Biology, Ausubel et al., eds. 1995 and supplements; Maniatis et al., in Molecular Cloning (A Laboratory Manual), Cold Spring Harbor Laboratory, 1982; Sambrook and Russell, in Molecular Cloning: A Laboratory Manual, 3rd edition 2001; each of which is incorporated herein by reference). An example of one such stringent hybridization conditions may be about 16-20 hours hybridization in 4×SSC at 65° C., followed by washing in 0.1×SSC at 65° C. for an hour, or 2 washes in 0.1×SSC at 65° C. each for 20 or 30 minutes. Alternatively, an exemplary stringent hybridization condition could be overnight (16-20 hours) in 50% formamide, 4×SSC at 42° C., followed by washing in 0.1×SSC at 65° C. for an hour, or 2 washes in 0.1×SSC at 65° C. each for 20 or 30 minutes, or overnight (16-20 hours), or hybridization in Church aqueous phosphate buffer (7% SDS; 0.5M NaPO4 buffer pH 7.2; 10 mM EDTA) at 65° C., with 2 washes either at 50° C. in 0.1×SSC, 0.1% SDS for 20 or 30 minutes each, or 2 washes at 65° C. in 2×SSC, 0.1% SDS for 20 or 30 minutes each.
Additionally, the present invention includes nucleotide sequences that are characterized as having about 70, 75, 80, 85, 87, 90, 91, 92, 93 94, 95, 96, 97, 98, 99, 100% or any amount therebetween, sequence identity, or sequence similarity, with the nucleotide sequence encoding chimeric HA according to the underlined portions of any one of SEQ ID NO: 63, SEQ ID NO: 64, SEQ ID NO: 65, SEQ ID NO: 68, SEQ ID NO: 69, SEQ ID NO: 71, SEQ ID NO: 72, SEQ ID NO: 74, SEQ ID NO: 75, wherein the nucleotide sequence encodes a hemagglutinin protein that when expressed forms a chimeric VLP, and that the chimeric VLP induces the production of an antibody. For example, expression of the nucleotide sequence within a plant cell forms a chimeric VLP, and the chimeric VLP may be used to produce an antibody that is capable of binding HA, including mature HA, HA0, HA1, or HA2. The VLP, when administered to a subject, induces an immune response.
An “immune response” generally refers to a response of the adaptive immune system. The adaptive immune system generally comprises a humoral response, and a cell-mediated response. The humoral response is the aspect of immunity that is mediated by secreted antibodies, produced in the cells of the B lymphocyte lineage (B cell). Secreted antibodies bind to antigens on the surfaces of invading microbes (such as viruses or bacteria), which flags them for destruction. Humoral immunity is used generally to refer to antibody production and the processes that accompany it, as well as the effector functions of antibodies, including Th2 cell activation and cytokine production, memory cell generation, opsonin promotion of phagocytosis, pathogen elimination and the like. The terms “modulate” or “modulation” or the like refer to an increase or decrease in a particular response or parameter, as determined by any of several assays generally known or used, some of which are exemplified herein.
A cell-mediated response is an immune response that does not involve antibodies but rather involves the activation of macrophages, natural killer cells (NK), antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. Cell-mediated immunity is used generally to refer to some Th cell activation, Tc cell activation and T-cell mediated responses. Cell mediated immunity is of particular importance in responding to viral infections.
For example, the induction of antigen specific CD8 positive T lymphocytes may be measured using an ELISPOT assay; stimulation of CD4 positive T-lymphocytes may be measured using a proliferation assay. Anti-influenza antibody titres may be quantified using an ELISA assay; isotypes of antigen-specific or cross reactive antibodies may also be measured using anti-isotype antibodies (e.g. anti-IgG, IgA, IgE or IgM). Methods and techniques for performing such assays are well-known in the art.
A hemagglutination inhibition (HI, or HAI) assay may also be used to demonstrate the efficacy of antibodies induced by a vaccine, or vaccine composition comprising chimeric HA or chimeric VLP can inhibit the agglutination of red blood cells (RBC) by recombinant HA. Hemagglutination inhibitory antibody titers of serum samples may be evaluated by microtiter HAI (Aymard et al 1973). Erythrocytes from any of several species may be used—e.g. horse, turkey, chicken or the like. This assay gives indirect information on assembly of the HA trimer on the surface of VLP, confirming the proper presentation of antigenic sites on HAs.
Cross-reactivity HAI titres may also be used to demonstrate the efficacy of an immune response to other strains of virus related to the vaccine subtype. For example, serum from a subject immunized with a vaccine composition comprising a chimeric hemagglutinin comprising an HDC of a first influenza type or subtype may be used in an HAI assay with a second strain of whole virus or virus particles, and the HAI titer determined.
Without wishing to be bound by theory, the capacity of HA to bind to RBC from different animals is driven by the affinity of HA for sialic acids bound with α2,3 or α2,6 linkages and the presence of these sialic acids on the surface of RBC. Equine and avian HA from influenza viruses agglutinate erythrocytes from all several species, including turkeys, chickens, ducks, guinea pigs, humans, sheep, horses and cows; whereas human HAs will bind to erythrocytes of turkey, chickens, ducks, guinea pigs, humans and sheep (Ito T. et al, 1997, Virology, 227:493-499; Medeiros R et al, 2001. Virology 289:74-85).
Cytokine presence or levels may also be quantified. For example a T-helper cell response (Th1/Th2) will be characterized by the measurement of IFN-γ and IL-4 secreting cells using by ELISA (e.g. BD Biosciences OptEIA kits). Peripheral blood mononuclear cells (PBMC) or splenocytes obtained from a subject may be cultured, and the supernatant analyzed. T lymphocytes may also be quantified by fluorescence-activated cell sorting (FACS), using marker specific fluorescent labels and methods as are known in the art.
A microneutralization assay may also be conducted to characterize an immune response in a subject, see for example the methods of Rowe et al., 1973. Virus neutralization titers may be obtained several ways, including: 1) enumeration of lysis plaques (plaque assay) following crystal violet fixation/coloration of cells; 2) microscopic observation of cell lysis in culture; 3) ELISA and spectrophotometric detection of NP virus protein (correlate with virus infection of host cells)
Sequence identity or sequence similarity may be determined using a sequence comparison program, such as that provided within DNASIS (for example, using, but not limited to, the following parameters: GAP penalty 5, #of top diagonals 5, fixed GAP penalty 10, k-tuple 2, floating gap 10, and window size 5). However, other methods of alignment of sequences for comparison are well-known in the art for example the algorithms of Smith & Waterman (1981, Adv. Appl. Math. 2:482), Needleman & Wunsch (J. Mol. Biol. 48:443, 1970), Pearson & Lipman (1988, Proc. Nat'l. Acad. Sci. USA 85:2444), and by computerized implementations of these algorithms (e.g. GAP, BESTFIT, FASTA, and BLAST (Altschul et al., 1990. J. Mol Biol 215:403-410), or by manual alignment and visual inspection. Nucleic acid or amino acid sequences may be compared or aligned and consensus sequences may be determined using any of several software packages known in the art, for example MULTALIN (Corpet F., 1988, Nucl. Acids Res., 16 (22), 10881-10890), BLAST, CLUSTAL or the like; alternately sequences may be aligned manually and similarities and differences between the sequences determined.
A fragment or portion of a protein, fusion protein or polypeptide includes a peptide or polypeptide comprising a subset of the amino acid complement of a particular protein or polypeptide, provided that the fragment can form a chimeric VLP when expressed. The fragment may, for example, comprise an antigenic region, a stress-response-inducing region, or a region comprising a functional domain of the protein or polypeptide. The fragment may also comprise a region or domain common to proteins of the same general family, or the fragment may include sufficient amino acid sequence to specifically identify the full-length protein from which it is derived.
For example, a fragment or portion may comprise from about 60% to about 100%, of the length of the full length of the protein, or any amount therebetween, provided that the fragment can form a chimeric VLP when expressed. For example, from about 60% to about 100%, from about 70% to about 100%, from about 80% to about 100%, from about 90% to about 100%, from about 95% to about 100%, of the length of the full length of the protein, or any amount therebetween. Alternately, a fragment or portion may be from about 150 to about 500 amino acids, or any amount therebetween, depending upon the chimeric HA, and provided that the fragment can form a chimeric VLP when expressed. For example, a fragment may be from 150 to about 500 amino acids, or any amount therebetween, from about 200 to about 500 amino acids, or any amount therebetween, from about 250 to about 500 amino acids, or any amount therebetween, from about 300 to about 500 or any amount therebetween, from about 350 to about 500 amino acids, or any amount therebetween, from about 400 to about 500 or any amount therebetween, from about 450 to about 500 or any amount therebetween, depending upon the chimeric HA, and provided that the fragment can form a chimeric VLP when expressed. For example, about 5, 10, 20, 30, 40 or 50 amino acids, or any amount therebetween may be removed from the C terminus, the N terminus or both the N and C terminus of a chimeric HA protein, provided that the fragment can form a chimeric VLP when expressed.
Numbering of amino acids in any given sequence are relative to the particular sequence, however one of skill can readily determine the ‘equivalency’ of a particular amino acid in a sequence based on structure and/or sequence. For example, if 6 N terminal amino acids were removed, this would change the specific numerical identity of the amino acid (e.g. relative to the full length of the protein), but would not alter the relative position of the amino acid in the structure.
The present invention describes, but is not limited to, expression of a nucleic acid encoding a chimeric HA in a plant portion of a plant, or a plant cell, and the production of chimeric influenza VLPs from the plant, suitable for vaccine production. Examples of such nucleic acids include, for example, but are not limited to, SEQ ID NO: 63, SEQ ID NO: 64, SEQ ID NO: 65, SEQ ID NO: 68, SEQ ID NO: 69, SEQ ID NO: 71, SEQ ID NO: 72, SEQ ID NO: 74, SEQ ID NO: 75.
The present invention further provides expression of a nucleic acid encoding a chimeric HA, for example but not limited to SEQ ID NO: 63, SEQ ID NO: 64, SEQ ID NO: 65, SEQ ID NO: 68, SEQ ID NO: 69, SEQ ID NO: 71, SEQ ID NO: 72, SEQ ID NO: 74, SEQ ID NO: 75 in a plant, a portion of a plant, or a plant cell, and production of influenza vaccine candidates or reagents comprised of recombinant influenza structural proteins that self-assemble into functional and immunogenic homotypic macromolecular protein structures, including subviral influenza particles and chimeric influenza VLP, in transformed plant cells.
Therefore, the invention provides for chimeric VLPs, and a method for producing chimeric VLPs in a plant expression system, from the expression of a single chimeric envelope protein.
The nucleic acid encoding the chimeric HA of influenza subtypes, for example SEQ ID NO: 63, SEQ ID NO: 64, SEQ ID NO: 65, SEQ ID NO: 68, SEQ ID NO: 69, SEQ ID NO: 71, SEQ ID NO: 72, SEQ ID NO: 74, SEQ ID NO: 75 may be synthesized by reverse transcription and polymerase chain reaction (PCR) using HA RNA. As an example, the RNA may be isolated from H1/NC, H1/Bri, H3/Bri, B/Flo or H5/Indo, or from cells infected with these or other influenza virus types or subtypes. For reverse transcription and PCR, oligonucleotide primers specific for the HA RNA may be used. Additionally, a nucleic acid encoding a chimeric HA may be chemically synthesized using methods as would be known to one of skill in the art.
The present invention is further directed to a gene construct comprising a nucleic acid encoding a chimeric HA, as described above, operatively linked to a regulatory element that is operative in a plant. Examples of regulatory elements operative in a plant cell and that may be used in accordance with the present invention include but are not limited to a plastocyanin regulatory region (U.S. Pat. No. 7,125,978; which is incorporated herein by reference), or a regulatory region of Ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO; U.S. Pat. No. 4,962,028; which is incorporated herein by reference), chlorophyll a/b binding protein (CAB; Leutwiler et al; 1986; which is incorporated herein by reference), ST-LS 1 (associated with the oxygen-evolving complex of photosystem II and described by Stockhaus et al.1987, 1989; which is incorporated herein by reference).
The gene constrcut of the present invention may also comprise a constitutive promoter that directs the expression of a gene that is operatively linked to the promoter throughout the various parts of a plant and continuously throughout plant development. A non-limiting example of a constitutive promoter is that associated with the CaMV 35S transcript (e.g. Odell et al., 1985, Nature, 313: 810-812, which is incorporated by reference).
An example of a sequence comprising a plastocyanin regulatory region is the sequence 5′ to the underlined sequenced encoding a PDI signal peptide of SEQ ID NO: 58. A regulatory element or regulatory region may enhance translation of a nucleotide sequence to which is it operatively linked, where the nucleotide sequence may encode a protein or polypeptide. Another example of a regulatory region, is that derived from the untranslated regions of the Cowpea Mosaic Virus (CPMV), which may be used to preferentially translate the nucleotide sequence to which it is operatively linked. This CPMV regulatory region is exploited in a hyper-translatable CMPV system (CPMV-HT; see, for example, Sainsbury et al, 2008, Plant Physiology 148: 1212-1218; Sainsbury et al., 2008 Plant Biotechnology Journal 6:82-92; both of which are incoprporated herein by reference).
Therefore, an aspect of the invention provides for a nucleic acid comprising a regulatory region operatively linked to a sequence encoding a chimeric influenza HA. The regulatory region may be a plastocyanin regulatory element, and the chimeric influenza HA may comprise subdomains from H5/Indo, H1/Bri, H3/Bri, H1/NC, B/Flo influenza types, subtypes or strains. Nucleic acid sequences comprising a plastocyanin regulatory element and a chimeric influenza HA are exemplified herein by SEQ ID NOs: 63 and 64. Nucleic acid sequences comprising a 35S regulatory element and a chimeric influenza HA are exemplified herein by SEQ ID NOs: 68, 69 and 71-75.
In another aspect, the invention provides for a nucleic acid comprising a CPMV regulatory region and a chimeric influenza HA, comprising subdomains from H5/Indo, H1/Bri, H3/Bri, H1/NC, B/Flo influenza types, subtypes or strains. Nucleic acid sequences comprising a CPMP regulatory element and a chimeric HA are exemplified herein by SEQ ID NOs: 66-69 and 71-75.
Plant-produced chimeric influenza VLPs bud from the plasma membrane and the lipid composition of the chimeric VLPs reflects that of the plant cell or plant tissue type from which they are produced. The VLPs produced according to the present invention comprise chimeric HA of two or more than two types or subtypes of influenza, complexed with plant derived lipids. Plant lipids can stimulate specific immune cells and enhance the immune response induced.
Plant lipids such as PC (phosphatidyl choline) and PE (phosphatidyl ethanolamine), as well as glycosphingolipids can bind to CD1 molecules expressed by mammalian immune cells such as antigen-presenting cells (APCs) like dendritic cells and macrophages and other cells including B and T lymphocytes in the thymus and liver (reviewed in Tsuji M,. 2006 Cell Mol Life Sci 63:1889-98). CD1 molecules are structurally similar to major histocompatibility complex (MHC) molecules of class I and their role is to present glycolipid antigens to NKT cells (Natural Killer T cells). Upon activation, NKT cells activate innate immune cells such as NK cells and dendritic cells and also activate adaptive immune cells like the antibody-producing B cells and T-cells.
The phytosterols present in an influenza VLP complexed with a lipid bilayer, such as an plasma-membrane derived envelope may provide for an advantageous vaccine composition. Without wishing to be bound by theory, plant-made VLPs, including those comprising chimeric HA, complexed with a lipid bilayer, such as a plasma-membrane derived envelope, may induce a stronger immune reaction than VLPs made in other expression systems, and may be similar to the immune reaction induced by live or attenuated whole virus vaccines.
Therefore, in some embodiments, the invention provides for a VLP comprising a chimeric HA, complexed with a plant-derived lipid bilayer. In some embodiments the plant-derived lipid bilayer may comprise the envelope of the VLP.
The VLP produced within a plant may include a chimeric HA comprising plant-specific N-glycans. Therefore, this invention also provides for a VLP comprising a chimeric HA having plant specific N-glycans.
Furthermore, modification of N-glycan in plants is known (see for example WO 2008/151440; which is incorporated herein by reference) and chimeric HA having modified N-glycans may be produced. A chimeric HA comprising a modified glycosylation pattern, for example with reduced fucosylated, xylosylated, or both, fucosylated and xylosylated, N-glycans may be obtained, or chimeric HA having a modified glycosylation pattern may be obtained, wherein the protein lacks fucosylation, xylosylation, or both, and comprises increased galatosylation. Furthermore, modulation of post-translational modifications, for example, the addition of terminal galactose may result in a reduction of fucosylation and xylosylation of the expressed chimeric HA when compared to a wild-type plant expressing chimeric HA.
For example, which is not to be considered limiting, the synthesis of chimeric
HA having a modified glycosylation pattern may be achieved by co-expressing the protein of interest along with a nucleotide sequence encoding beta-1,4galactosyltransferase (GalT), for example, but not limited to mammalian GalT, or human GalT however GalT from another sources may also be used. The catalytic domain of GalT may also be fused to a CTS domain (i.e. the cytoplasmic tail, transmembrane domain, stem region) of N-acetylglucosaminyl transferase (GNT1), to produce a GNT1-GalT hybrid enzyme, and the hybrid enzyme may be co-expressed with HA. The HA may also be co-expressed along with a nucleotide sequence encoding N-acetylglucosaminyltrasnferase III (GnT-III), for example but not limited to mammalian GnT-III or human GnT-III, GnT-III from other sources may also be used. Additionally, a GNT1-GnT-III hybrid enzyme, comprising the CTS of GNT1 fused to GnT-III may also be used.
Therefore the present invention also includes VLP's comprising chimeric HA having modified N-glycans.
Without wishing to be bound by theory, the presence of plant N-glycans on a chimeric HA may stimulate the immune response by promoting the binding of HA by antigen presenting cells. Stimulation of the immune response using plant N glycan has been proposed by Saint-Jore-Dupas et al. (Trends Biotechnol 25: 317-23, 2007). Furthermore, the conformation of the VLP may be advantageous for the presentation of the antigen, and enhance the adjuvant effect of VLP when complexed with a plant derived lipid layer.
By “regulatory region”, “regulatory element” or “promoter” it is meant a portion of nucleic acid typically, but not always, upstream of the protein coding region of a gene, which may be comprised of either DNA or RNA, or both DNA and RNA. When a regulatory region is active, and in operative association, or operatively linked, with a gene of interest, this may result in expression of the gene of interest. A regulatory element may be capable of mediating organ specificity, or controlling developmental or temporal gene activation. A “regulatory region” includes promoter elements, core promoter elements exhibiting a basal promoter activity, elements that are inducible in response to an external stimulus, elements that mediate promoter activity such as negative regulatory elements or transcriptional enhancers. “Regulatory region”, as used herein, also includes elements that are active following transcription, for example, regulatory elements that modulate gene expression such as translational and transcriptional enhancers, translational and transcriptional repressors, upstream activating sequences, and mRNA instability determinants Several of these latter elements may be located proximal to the coding region.
In the context of this disclosure, the term “regulatory element” or “regulatory region” typically refers to a sequence of DNA, usually, but not always, upstream (5′) to the coding sequence of a structural gene, which controls the expression of the coding region by providing the recognition for RNA polymerase and/or other factors required for transcription to start at a particular site. However, it is to be understood that other nucleotide sequences, located within introns, or 3′ of the sequence may also contribute to the regulation of expression of a coding region of interest. An example of a regulatory element that provides for the recognition for RNA polymerase or other transcriptional factors to ensure initiation at a particular site is a promoter element. Most, but not all, eukaryotic promoter elements contain a TATA box, a conserved nucleic acid sequence comprised of adenosine and thymidine nucleotide base pairs usually situated approximately 25 base pairs upstream of a transcriptional start site. A promoter element comprises a basal promoter element, responsible for the initiation of transcription, as well as other regulatory elements (as listed above) that modify gene expression.
There are several types of regulatory regions, including those that are developmentally regulated, inducible or constitutive. A regulatory region that is developmentally regulated, or controls the differential expression of a gene under its control, is activated within certain organs or tissues of an organ at specific times during the development of that organ or tissue. However, some regulatory regions that are developmentally regulated may preferentially be active within certain organs or tissues at specific developmental stages, they may also be active in a developmentally regulated manner, or at a basal level in other organs or tissues within the plant as well. Examples of tissue-specific regulatory regions, for example see-specific a regulatory region, include the napin promoter, and the cruciferin promoter (Rask et al., 1998, J. Plant Physiol. 152: 595-599; Bilodeau et al., 1994, Plant Cell 14: 125-130). An example of a leaf-specific promoter includes the plastocyanin promoter (see, for example SEQ ID NO: 58); U.S. Pat. No. 7,125,978, which is incorporated herein by reference).
An inducible regulatory region is one that is capable of directly or indirectly activating transcription of one or more DNA sequences or genes in response to an inducer. In the absence of an inducer the DNA sequences or genes will not be transcribed. Typically the protein factor that binds specifically to an inducible regulatory region to activate transcription may be present in an inactive form, which is then directly or indirectly converted to the active form by the inducer. However, the protein factor may also be absent. The inducer can be a chemical agent such as a protein, metabolite, growth regulator, herbicide or phenolic compound or a physiological stress imposed directly by heat, cold, salt, or toxic elements or indirectly through the action of a pathogen or disease agent such as a virus. A plant cell containing an inducible regulatory region may be exposed to an inducer by externally applying the inducer to the cell or plant such as by spraying, watering, heating or similar methods. Inducible regulatory elements may be derived from either plant or non-plant genes (e.g. Gatz, C. and Lenk, I. R. P., 1998, Trends Plant Sci. 3, 352-358; which is incorporated by reference). Examples, of potential inducible promoters include, but not limited to, tetracycline-inducible promoter (Gatz, C.,1997, Ann. Rev. Plant Physiol. Plant Mol. Biol. 48, 89-108; which is incorporated by reference), steroid inducible promoter (Aoyama, T. and Chua, N. H., 1997, Plant J. 2, 397-404; which is incorporated by reference) and ethanol-inducible promoter (Salter, M. G., et al, 1998, Plant Journal 16, 127-132; Caddick, M. X., et al, 1998, Nature Biotech. 16, 177-180, which are incorporated by reference) cytokinin inducible IB6 and CKI1 genes (Brandstatter, I. and Kieber, J. J., 1998, Plant Cell 10, 1009-1019; Kakimoto, T., 1996, Science 274, 982-985; which are incorporated by reference) and the auxin inducible element, DR5 (Ulmasov, T., et al., 1997, Plant Cell 9, 1963-1971; which is incorporated by reference).
A constitutive regulatory region directs the expression of a gene throughout the various parts of a plant and continuously throughout plant development. Examples of known constitutive regulatory elements include promoters associated with the CaMV 35S transcript. (Odell et al., 1985, Nature, 313: 810-812), the rice actin 1 (Zhang et al, 1991, Plant Cell, 3: 1155-1165), actin 2 (An et al., 1996, Plant J., 10: 107-121), or tms 2 (U.S. Pat. No. 5,428,147, which is incorporated herein by reference), and triosephosphate isomerase 1 (Xu et. al., 1994, Plant Physiol. 106: 459-467) genes, the maize ubiquitin 1 gene (Cornejo et al, 1993, Plant Mol. Biol. 29: 637-646), the Arabidopsis ubiquitin 1 and 6 genes (Holtorf et al, 1995, Plant Mol. Biol. 29: 637-646), and the tobacco translational initiation factor 4A gene (Mandel et al, 1995 Plant Mol. Biol. 29: 995-1004). The term “constitutive” as used herein does not necessarily indicate that a gene under control of the constitutive regulatory region is expressed at the same level in all cell types, but that the gene is expressed in a wide range of cell types even though variation in abundance is often observed. Constitutive regulatory elements may be coupled with other sequences to further enhance the transcription and/or translation of the nucleotide sequence to which they are operatively linked. For example, the CPMV-HT system is derived from the untranslated regions of the Cowpea mosaic virus (CPMV) and demonstrates enhanced translation of the associated coding sequence.
By “native” it is meant that the nucleic acid or amino acid sequence is naturally occurring, or “wild type”.
By “operatively linked” it is meant that the particular sequences, for example a regulatory element and a coding region of interest, interact either directly or indirectly to carry out an intended function, such as mediation or modulation of gene expression. The interaction of operatively linked sequences may, for example, be mediated by proteins that interact with the operatively linked sequences.
The one or more than one nucleotide sequence of the present invention may be expressed in any suitable plant host that is transformed by the nucleotide sequence, or constructs, or vectors of the present invention. Examples of suitable hosts include, but are not limited to, agricultural crops including alfalfa, canola, Brassica spp., maize, Nicotiana spp., alfalfa, potato, ginseng, pea, oat, rice, soybean, wheat, barley, sunflower, cotton and the like.
The one or more chimeric genetic constructs of the present invention can further comprise a 3′ untranslated region. A 3′ untranslated region refers to that portion of a gene comprising a DNA segment that contains a polyadenylation signal and any other regulatory signals capable of effecting mRNA processing or gene expression. The polyadenylation signal is usually characterized by effecting the addition of polyadenylic acid tracks to the 3′ end of the mRNA precursor. Polyadenylation signals are commonly recognized by the presence of homology to the canonical form 5′ AATAAA-3′ although variations are not uncommon.
Non-limiting examples of suitable 3′ regions are the 3′ transcribed non-translated regions containing a polyadenylation signal of Agrobacterium tumor inducing (Ti) plasmid genes, such as the nopaline synthase (NOS) gene, plant genes such as the soybean storage protein genes, the small subunit of the ribulose-1,5-bisphosphate carboxylase gene (ssRUBISCO; U.S. Pat. No. 4,962,028; which is incorporated herein by reference), the promoter used in regulating plastocyanin expression, described in U.S. Pat. No. 7,125,978 (which is incorporated herein by reference).
One or more of the chimeric genetic constructs of the present invention may also include further enhancers, either translation or transcription enhancers, as may be required. Enhancers may be located 5′ or 3′ to the sequence being transcribed. Enhancer regions are well known to persons skilled in the art, and may include an ATG initiation codon, adjacent sequences or the like. The initiation codon, if present, may be in phase with the reading frame (“in frame”) of the coding sequence to provide for correct translation of the transcribed sequence.
To aid in identification of transformed plant cells, the constructs of this invention may be further manipulated to include plant selectable markers. Useful selectable markers include enzymes that provide for resistance to chemicals such as an antibiotic for example, gentamycin, hygromycin, kanamycin, or herbicides such as phosphinothrycin, glyphosate, chlorosulfuron, and the like. Similarly, enzymes providing for production of a compound identifiable by colour change such as GUS (beta-glucuronidase), or luminescence, such as luciferase or GFP, may be used.
Also considered part of this invention are transgenic plants, plant cells or seeds containing the chimeric gene construct of the present invention. Methods of regenerating whole plants from plant cells are also known in the art. In general, transformed plant cells are cultured in an appropriate medium, which may contain selective agents such as antibiotics, where selectable markers are used to facilitate identification of transformed plant cells. Once callus forms, shoot formation can be encouraged by employing the appropriate plant hormones in accordance with known methods and the shoots transferred to rooting medium for regeneration of plants. The plants may then be used to establish repetitive generations, either from seeds or using vegetative propagation techniques. Transgenic plants can also be generated without using tissue cultures.
Also considered part of this invention are transgenic plants, trees, yeast, bacteria, fungi, insect and animal cells containing the chimeric gene construct comprising a nucleic acid encoding recombinant, chimeric HA or HA0 for VLP production, in accordance with the present invention.
The regulatory elements of the present invention may also be combined with coding region of interest for expression within a range of host organisms that are amenable to transformation, or transient expression. Such organisms include, but are not limited to plants, both monocots and dicots, for example but not limited to corn, cereal plants, wheat, barley, oat, Nicotiana spp, Brassica spp, soybean, bean, pea, alfalfa, potato, tomato, ginseng, and Arabidopsis.
Methods for stable transformation, and regeneration of these organisms are established in the art and known to one of skill in the art. The method of obtaining transformed and regenerated plants is not critical to the present invention.
By “transformation” it is meant the interspecific transfer of genetic information (nucleotide sequence) that is manifested genotypically, phenotypically or both. The interspecific transfer of genetic information from a chimeric construct to a host may be heritable and the transfer of genetic information considered stable, or the transfer may be transient and the transfer of genetic information is not inheritable.
By the term “plant matter”, it is meant any material derived from a plant. Plant matter may comprise an entire plant, tissue, cells, or any fraction thereof. Further, plant matter may comprise intracellular plant components, extracellular plant components, liquid or solid extracts of plants, or a combination thereof. Further, plant matter may comprise plants, plant cells, tissue, a liquid extract, or a combination thereof, from plant leaves, stems, fruit, roots or a combination thereof. Plant matter may comprise a plant or portion thereof which has not been subjected to any processing steps. A portion of a plant may comprise plant matter. However, it is also contemplated that the plant material may be subjected to minimal processing steps as defined below, or more rigorous processing, including partial or substantial protein purification using techniques commonly known within the art including, but not limited to chromatography, electrophoresis and the like.
By the term “minimal processing” it is meant plant matter, for example, a plant or portion thereof comprising a protein of interest which is partially purified to yield a plant extract, homogenate, fraction of plant homogenate or the like (i.e. minimally processed). Partial purification may comprise, but is not limited to disrupting plant cellular structures thereby creating a composition comprising soluble plant components, and insoluble plant components which may be separated for example, but not limited to, by centrifugation, filtration or a combination thereof. In this regard, proteins secreted within the extracellular space of leaf or other tissues could be readily obtained using vacuum or centrifugal extraction, or tissues could be extracted under pressure by passage through rollers or grinding or the like to squeeze or liberate the protein free from within the extracellular space. Minimal processing could also involve preparation of crude extracts of soluble proteins, since these preparations would have negligible contamination from secondary plant products. Further, minimal processing may involve aqueous extraction of soluble protein from leaves, followed by precipitation with any suitable salt. Other methods may include large scale maceration and juice extraction in order to permit the direct use of the extract.
The plant matter, in the form of plant material or tissue may be orally delivered to a subject. The plant matter may be administered as part of a dietary supplement, along with other foods, or encapsulated. The plant matter or tissue may also be concentrated to improve or increase palatability, or provided along with other materials, ingredients, or pharmaceutical excipients, as required.
Examples of a subject or target organism that the VLPs of the present invention may be administered to include, but are not limited to, humans, primates, birds, water fowl, migratory birds, quail, duck, geese, poultry, chicken, swine, sheep, equine, horse, camel, canine, dogs, feline, cats, tiger, leopard, civet, mink, stone marten, ferrets, house pets, livestock, rabbits, mice, rats, guinea pigs or other rodents, seal, whale and the like. Such target organisms are exemplary, and are not to be considered limiting to the applications and uses of the present invention.
It is contemplated that a plant comprising the chimeric HA according to some embodiments of the invention, or expressing the VLP comprising the chimeric HA according to some embodiments of the invention, may be administered to a subject or target organism, in a variety of ways depending upon the need and the situation. For example, the chimeric HA obtained from the plant may be extracted prior to its use in either a crude, partially purified, or purified form. If the chimeric HA is to be at least partially purified, then it may be produced in either edible or non-edible plants. Furthermore, if the chimeric HA is orally administered, the plant tissue may be harvested and directly feed to the subject, or the harvested tissue may be dried prior to feeding, or an animal may be permitted to graze on the plant with no prior harvest taking place. It is also considered within the scope of this invention for the harvested plant tissues to be provided as a food supplement within animal feed. If the plant tissue is being feed to an animal with little or not further processing it is preferred that the plant tissue being administered is edible.
Post-transcriptional gene silencing (PTGS) may be involved in limiting expression of transgenes in plants, and co-expression of a suppressor of silencing from the potato virus Y (HcPro) may be used to counteract the specific degradation of transgene mRNAs (Brigneti et al., 1998). Alternate suppressors of silencing are well known in the art and may be used as described herein (Chiba et al., 2006, Virology 346:7-14; which is incorporated herein by reference), for example but not limited to, TEV-p1/HC-Pro (Tobacco etch virus-p1/HC-Pro), BYV-p21, p19 of Tomato bushy stunt virus (TBSV p19), capsid protein of Tomato crinkle virus (TCV-CP), 2b of Cucumber mosaic virus; CMV-2b), p25 of Potato virus X (PVX-p25), p11 of Potato virus M (PVM-p11), p11 of Potato virus S (PVS-p11), p16 of Blueberry scorch virus, (BScV-p16), p23 of Citrus tristeza virus (CTV-p23), p24 of Grapevine leafroll-associated virus-2, (GLRaV-2 p24), p10 of Grapevine virus A, (GVA-p10), p14 of Grapevine virus B (GVB-p14), p10 of Heracleum latent virus (HLV-p10), or p16 of Garlic common latent virus (GCLV-p 16). Therefore, a suppressor of silencing, for example, but not limited to, HcPro, TEV-p1/HC-Pro, BYV-p21, TBSV p19, TCV-CP, CMV-2b, PVX-p25, PVM-p11, PVS-p11, BScV-p16, CTV-p23, GLRaV-2 p24, GBV-p14, HLV-p10, GCLV-p16 or GVA-p10, may be co-expressed along with the nucleic acid sequence encoding the protein of interest to further ensure high levels of protein production within a plant.
Furthermore, VLPs produced as described herein do not comprise neuraminidase (NA). However, NA may be co-expressed with HA should VLPs comprising HA and NA be desired.
Therefore, the present invention further includes a suitable vector comprising the chimeric HA sequence suitable for use with either stable or transient expression systems. The genetic information may be also provided within one or more than one construct. For example, a nucleotide sequence encoding a protein of interest may be introduced in one construct, and a second nucleotide sequence encoding a protein that modifies glycosylation of the protein of interest may be introduced using a separate construct. These nucleotide sequences may then be co-expressed within a plant. However, a construct comprising a nucleotide sequence encoding both the protein of interest and the protein that modifies glycosylation profile of the protein of interest may also be used. In this case the nucleotide sequence would comprise a first sequence comprising a first nucleic acid sequence encoding the protein of interest operatively linked to a promoter or regulatory region, and a second sequence comprising a second nucleic acid sequence encoding the protein that modifies the glycosylation profile of the protein of interest, the second sequence operatively linked to a promoter or regulatory region.
By “co-expressed” it is meant that two, or more than two, nucleotide sequences are expressed at about the same time within the plant, and within the same tissue of the plant. However, the nucleotide sequences need not be expressed at exactly the same time. Rather, the two or more nucleotide sequences are expressed in a manner such that the encoded products have a chance to interact. For example, the protein that modifies glycosylation of the protein of interest may be expressed either before or during the period when the protein of interest is expressed so that modification of the glycosylation of the protein of interest takes place. The two or more than two nucleotide sequences can be co-expressed using a transient expression system, where the two or more sequences are introduced within the plant at about the same time under conditions that both sequences are expressed. Alternatively, a platform plant comprising one of the nucleotide sequences, for example the sequence encoding the protein that modifies the glycosylation profile of the protein of interest, may be transformed, either transiently or in a stable manner, with an additional sequence encoding the protein of interest. In this case, the sequence encoding the protein that modifies the glycosylation profile of the protein of interest may be expressed within a desired tissue, during a desired stage of development, or its expression may be induced using an inducible promoter, and the additional sequence encoding the protein of interest may be expressed under similar conditions and in the same tissue, to ensure that the nucleotide sequences are co-expressed.
The constructs of the present invention can be introduced into plant cells using Ti plasmids, Ri plasmids, plant virus vectors, direct DNA transformation, micro-injection, electroporation, infiltration, and the like. For reviews of such techniques see for example Weissbach and Weissbach, Methods for Plant Molecular Biology, Academy Press, New York VIII, pp. 421-463 (1988); Geierson and Corey, Plant Molecular Biology, 2d Ed. (1988); and Miki and Iyer, Fundamentals of Gene Transfer in Plants. In Plant Metabolism, 2d Ed. D T. Dennis, D H Turpin, D D Lefebrve, D B Layzell (eds), Addison-Wesley, Langmans Ltd. London, pp. 561-579 (1997). Other methods include direct DNA uptake, the use of liposomes, electroporation, for example using protoplasts, micro-injection, microprojectiles or whiskers, and vacuum infiltration. See, for example, Bilang, et al. (Gene 100: 247-250 (1991), Scheid et al. (Mol. Gen. Genet. 228: 104-112, 1991), Guerche et al. (Plant Science 52: 111-116, 1987), Neuhause et al. (Theor. Appl Genet. 75: 30-36, 1987), Klein et al., Nature 327: 70-73 (1987); Howell et al. (Science 208: 1265, 1980), Horsch et al. (Science 227: 1229-1231, 1985), DeBlock et al., Plant Physiology 91: 694-701, 1989), Liu and Lomonossoff (J. Virol Meth, 105:343-348, 2002,), U.S. Pat. Nos. 4,945,050; 5,036,006; 5,100,792; 6,403,865; 5,625,136, (all of which are hereby incorporated by reference).
Transient expression methods may be used to express the constructs of the present invention (see Liu and Lomonossoff, 2002, Journal of Virological Methods, 105:343-348; which is incorporated herein by reference). Alternatively, a vacuum-based transient expression method, as described by Kapila et al. 1997 Plant Science 122:101-108 (incorporated herein by reference) may be used. These methods may include, for example, but are not limited to, a method of Agro-inoculation or Agro-infiltration, however, other transient methods may also be used as noted above. With either Agro-inoculation or Agro-infiltration, a mixture of Agrobacteria comprising the desired nucleic acid enter the intercellular spaces of a tissue, for example the leaves, aerial portion of the plant (including stem, leaves and flower), other portion of the plant (stem, root, flower), or the whole plant. After crossing the epidermis the Agrobacterium infect and transfer t-DNA copies into the cells. The t-DNA is episomally transcribed and the mRNA translated, leading to the production of the protein of interest in infected cells, however, the passage of t-DNA inside the nucleus is transient.
The VLPs comprising chimeric HA provided by the present invention may be used in conjunction with an existing influenza vaccine, to supplement the vaccine, render it more efficacious, or to reduce the administration dosages necessary. As would be known to a person of skill in the art, the vaccine may be directed against one or more than one influenza virus. Examples of suitable vaccines include, but are not limited to, those commercially available from Sanofi-Pasteur, ID Biomedical, Merial, Sinovac, Chiron, Roche, MedImmune, GlaxoSmithKline, Novartis, Sanofi-Aventis, Serono, Shire Pharmaceuticals and the like.
If desired, the VLPs of the present invention may be admixed with a suitable adjuvant as would be known to one of skill in the art. Furthermore, the VLP may be used in a vaccine composition comprising an effective dose of the VLP for the treatment of a target organism, as defined above. Furthermore, the VLP produced according to the present invention may be combined with VLPs obtained using different influenza proteins, for example, neuraminidase (NA).
Therefore, the present invention provides a method for inducing immunity to influenza virus infection in an animal or target organism comprising administering an effective dose of a vaccine comprising one or more than one VLP. The vaccine may be administered orally, intradermally, intranasally, intramuscularly, intraperitoneally, intravenously, or subcutaneously.
Compositions according to various embodiments of the invention may comprise VLPs of two or more influenza strains or subtypes. “Two or more” refers to two, three, four, five, six, seven, eight, nine, 10 or more strains or subtypes. The strains or subtypes represented may be of a single subtype (e.g. all H1N1, or all H5N1), or may be a combination of subtypes. Exemplary subtype and strains include H5/Indo, H1/Bri, H1/NC, H3/Bri, B/Flo. The choice of combination of strains and subtypes may depend on the geographical area of the subjects likely to be exposed to influenza, proximity of animal species to a human population to be immunized (e.g. species of waterfowl, agricultural animals such as swine, etc) and the strains they carry, are exposed to or are likely to be exposed to, predictions of antigenic drift within subtypes or strains, or combinations of these factors. Examples of combinations used in past years are available in the databases maintained by the World Health Organization (WHO) (see URL: who.int/csr/dieease/influenza/vaccine recommendations1/en).
The two or more VLPs may be expressed individually, and the purified or semi-purified VLPs subsequently combined. Alternately, the VLPs may be co-expressed in the same host, for example a plant, protion of plant, or plant cell. The VLPs may be combined or produced in a desired ratio, for example about equivalent ratios, or may be combined in such a manner that one subtype or strain comprises the majority of the VLPs in the composition.
Therefore, the invention provides for compositions comprising VLPs of two or more strains or subtypes.
Also provided is an article of manufacture, comprising packaging material and a composition comprising a VLP comprising a chimeric HA. The composition includes a physiologically or pharmaceutically acceptable excipient, and the packaging material may include a label which indicates the active ingredients of the composition (e.g. the VLP).
A kit comprising a composition comprising a nucleic acid encoding a chimeric HA as provided herein, along with instructions for use of the nucleic acid for production of chimeric HA, or VLPs comprising the chimeric HA is also provided. The kit may be useful for production of VLPs comprising the chimeric HA, and the instructions may include, for example, information on expressing the nucleic acid in a plant or a plant cell, instructions for harvesting and obtaining the VLPs from the plant or plant tissue.
In another embodiment, a kit for the preparation of a medicament, comprising a VLP comprising a chimeric HA, along with instructions for its use is provided. The instructions may comprise a series of steps for the preparation of the medicament, the medicament being useful for inducing a therapeutic or prophylactic immune response in a subject to whom it is administered. The kit may further comprise instructions addressing dose concentrations, dose intervals, preferred administration methods or the like.
The present invention will be further illustrated in the following examples. However it is to be understood that these examples are for illustrative purposes only, and should not be used to limit the scope of the present invention in any manner.
The sequences described herein are summarized below.
1. Assembly of HA Expression Cassettes
A—pCAMBIAPlasto
All manipulations were done using the general molecular biology protocols of Sambrook and Russell (2001; which is incorporated herein by reference). Table 1 presents oligonucleotide primers used for expression cassettes assembly. The first cloning step consisted in assembling a receptor plasmid containing upstream and downstream regulatory elements of the alfalfa plastocyanin gene. The plastocyanin promoter and 5′UTR sequences were amplified from alfalfa genomic DNA using oligonucleotide primers XmaI-pPlas.c (SEQ ID NO:1) and SacI-ATG-pPlas.r (SEQ ID NO:2). The resulting amplification product was digested with XmaI and SacI and ligated into pCAMBIA2300 (Cambia, Canberra, Australia), previously digested with the same enzymes, to create pCAMBIApromoPlasto. Similarly, the 3′UTR sequences and terminator of the plastocyanin gene was amplified from alfalfa genomic DNA using the following primers: SacI-PlasTer.c (SEQ ID NO:3) and EcoRI-PlasTer.r (SEQ ID NO:4), and the product was digested with SacI and EcoRI before being inserted into the same sites of pCAMBIApromoPlasto to create pCAMBIAPlasto.
A fragment encoding hemagglutinin from influenza strain A/Indonesia/5/05 (H5N1; Acc. No. LANL ISDN125873) was synthesized by Epoch Biolabs (Sugar Land, Tex., USA). The fragment produced, containing the complete H5 coding region including the native signal peptide flanked by a HindIII site immediately upstream of the initial ATG, and a SacI site immediately downstream of the stop (TAA) codon, is presented in (SEQ ID NO:52;
The open reading frame from the H1 gene of influenza strain A/New Caledonia/20/99 (H1N1) was synthesized in two fragments (Plant Biotechnology Institute, National Research Council, Saskatoon, Canada). A first fragment synthesized corresponds to the wild-type H1 coding sequence (GenBank ace. No. AY289929; SEQ ID NO: 54;
The first H1 fragment was digested with BglII and SacI and cloned into the same sites of a binary vector (pCAMBIAPlasto) containing the plastocyanin promoter and 5′ UTR fused to the signal peptide of alfalfa protein disulfide isomerase (PDI) gene (nucleotides 32-103; Accession No. Z11499; SEQ ID NO: 57;
Expression cassette number 774, driving the expression of H1 from A/Brisbane/59/07, was assembled as follows. A synthetic fragment was synthesized comprising the complete hemagglutinin coding sequence (from ATG to stop) flanked in 3′ by alfalfa plastocyanin gene sequences corresponding to the first 84 nucleotides upstream of the plastocyanin ATG starting with a DraIII restriction site. The synthetic fragments also comprised a SacI site immediately downstream of the stop codon.
The synthetic fragment was synthesized by Top Gene Technologies (Montreal, QC, Canada). The fragment synthesized is presented in SEQ ID NO. 60 (
CPMV-HT expression cassettes use the 35S promoter to control the expression of an mRNA comprising a coding sequence of interest flanked, in 5′, by nucleotides 1-512 from the Cowpea mosaic virus (CPMV) RNA2 with mutated ATG at positions 115 and 161, and in 3′, by nucleotides 3330-3481 from the CPMV RNA2 (corresponding to the 3′ UTR) followed by the NOS terminator. Plasmid pBD-C5-1LC, (Sainsbury et al. 2008; Plant Biotechnology Journal 6: 82-92 and PCT Publication WO 2007/135480), was used for the assembly of CPMV-HT-based hemagglutinin expression cassettes. The mutation of ATGs at position 115 and 161 of the CPMV RNA2 was done using a PCR-based ligation method presented in Darveau et al. (Methods in Neuroscience 26: 77-85 (1995)). Two separate PCRs were performed using pBD-C5-1LC as template. The primers for the first amplification were pBinPlus.2613c (SEQ ID NO: 9) and Mut-ATG115.r (SEQ ID NO: 10). The primers for the second amplification were Mut-ATG161.c (SEQ ID NO: 11) and LC-C5-1.110r (SEQ ID NO: 12). The two fragments obtained were mixed and used as template for a third amplification using pBinPlus.2613c (SEQ ID NO: 9) and LC-C5-1.110r (SEQ ID NO: 12) as primers. The resulting fragment was digested with PacI and ApaI and cloned into pBD-05-ILC digested with the same enzymes. The construct generated, named 828, is presented in
A chimeric HA was made by replacing the RB domain in the H5 A/Indonesia/5/05 with that of H1 A/Brisbane/59/07 using the PCR-based ligation method presented in Darveau et al. (Methods in Neuroscience 26: 77-85(1995)). In a first round of PCR, a segment of the plastocyanin promoter fused to the natural signal peptide, the F′1 and E1 domains of the H5 A/Indonesia/5/05 was amplified using primers Plasto-443c (SEQ ID NO: 5) and E1 H1B-E1 H5I.r (SEQ ID NO:13) with construct number 660 (SEQ ID NO:53,
A chimeric HA was assembled by replacing the E1-RB-E2 domains in H5 A/Indonesia/5/05 with those of H1 A/Brisbane/59/07 using the PCR-based ligation method presented in Darveau et al. (Methods in Neuroscience 26: 77-85(1995)). In a first round of PCR, a segment of the plastocyanin promoter fused to the natural signal peptide and the F′1 domain of H5 A/Indonesia/5/05 was amplified using primers Plasto-443c (SEQ ID NO:5) and E1 H1B-F′1 H51.r (SEQ ID NO: 17) with construct number 660 (SEQ ID NO: 53;
A chimeric HA was made by replacing the RB domain in the H1 A/New Caledonia/20/99 with that of H5 A/Indonesia/5/05 using the PCR-based ligation method presented in Darveau et al. (Methods in Neuroscience 26: 77-85(1995)). In a first round of PCR, a segment of the plastocyanin promoter fused to the signal peptide of alfalfa protein disulfide isomerase (PDISP; Accession No. Z11499; nucleotides 32-103 of SEQ ID NO: 57;
The coding sequence of HA from H1 A/Brisbane/59/2007 was cloned into CPMV-HT as follows. Restriction sites ApaI (immediately upstream of ATG) and StuI (immediately downstream of the stop codon) were added to the hemagglutinin coding sequence by performing a PCR amplification with primers ApaI-H1B.c (SEQ ID NO: 26) and StuI-H1B.r (SEQ ID NO: 27) using construct number 774 (SEQ ID NO: 61;
A sequence encoding the signal peptide of alfalfa protein disulfide isomerase (PDISP; nucleotides 32-103 of SEQ ID NO: 57
The coding sequence of chimeric HA consisting in RB domain from H1 A/Brisbane/59/07 in H5 A/Indonesia/5/05 backbone was cloned into CPMV-HT as follows. Restriction sites ApaI (immediately upstream of ATG) and StuI (immediately downstream of the stop codon) were added to the chimeric hemagglutinin coding sequence by performing a PCR amplification with primers ApaI-H5 (A-Indo).1c (SEQ ID NO: 31) and H5 (A-Indo)-StuI.1707r (SEQ ID NO: 32) using construct number 690 (SEQ ID NO: 63;
A sequence encoding alfalfa PDI signal peptide fused to HA0 from H3 A/Brisbane/10/2007 was cloned into CPMV-HT as follows. First, a synthetic fragment was synthesized comprising the complete hemagglutinin coding sequence (from ATG to stop) flanked in 3′ by alfalfa plastocyanin gene sequence corresponding to the first 84 nucleotides (starting with a DraIII restriction site) upstream of the plastocyanin ATG. The synthetic fragment also comprised a SacI site immediately after the stop codon. Synthetic fragment was synthesized by Top Gene Technologies (Montreal, QC, Canada). The fragment synthesized is presented in SEQ ID NO: 70 (
Second, the signal peptide of alfalfa protein disulfide isomerase (PDISP) (nucleotides 32-103; Accession No Z11499; SEQ ID NO: 57;
A sequence encoding alfalfa PDI signal peptide fused to the ectodomain of H3 A/Brisbane/10/2007 and to the transmembrane and cytoplasmic domains of H5 A/Indonesia/5/2005 was cloned into CPMV-HT as follows. PDISP-H3 coding sequence was fused to the H5 transmembrane domain by the PCR-based ligation method presented in Darveau et al. (Methods in Neuroscience 26: 77-85(1995)). In a first round of PCR, a fragment comprising PDISP signal peptide and ectodomain from H3 Brisbane was generated by amplification (with ApaI restriction site upstream of the PDISP initial ATG) using primers ApaI-SpPDI.c (SEQ ID NO: 30) and TmD H5I-H3B.r (SEQ ID NO: 36) with construct number 736 (SEQ ID NO: 71;
A sequence encoding alfalfa PDI signal peptide fused to HA0 from HA B/Florida/4/2006 was cloned into CPMV-HT as follows. First, a synthetic fragment was synthesized comprising the complete hemagglutinin coding sequence (from ATG to stop) flanked in 3′ by alfalfa plastocyanin gene sequence corresponding to the first 84 nucleotides (starting with a DraIII restriction site) upstream of the plastocyanin ATG. The synthetic fragment also comprised a SacI restriction site immediately after the stop codon. The synthetic fragment was synthesized by Epoch Biolabs (Sugar Land, Tex., USA). The fragment synthesized is presented in SEQ ID NO: 73 (
Second, the signal peptide of alfalfa protein disulfide isomerase (PDISP) (nucleotides 32-103 of SEQ ID NO: 57;
A sequence encoding alfalfa PDI signal peptide fused to the ectodomain from HA B/Florida/4/2006 and to the transmembrane and cytoplasmic domains of H5 A/Indonesia/5/2005 was cloned into CPMV-HT as follows. PDISP-B/Florida/4/2006 ectodomain coding sequence was fused to the H5 transmembrane and cytoplasmic domains by the PCR-based ligation method presented in Darveau et al. (Methods in Neuroscience 26: 77-85(1995)). In a first round of PCR, a fragment comprising PDISP signal peptide fused to the ectodomain from HA B/Florida/4/2006 was generated by amplification using primers ApaI-SpPDI.c (SEQ ID NO: 30) and TmD H5I-B Flo.r (SEQ ID NO: 41) with construct number 739 (SEQ ID NO: 74;
A sequence encoding alfalfa PDI signal peptide fused to HA0 from HA B/Florida/4/2006 and to the transmembrane and cytoplasmic domain of H5 A/Indonesia/5/2005 was cloned into 2X35S-CPMV-HT as follows. The promoter switch was performed using the PCR-based ligation method presented in Darveau et al. (Methods in Neuroscience 26: 77-85 (1995)). A first fragment containing 2X35S promoter (SEQ ID NO: 88;
using a plasmid containing the 2X35S promoter as template. In parallel, a second PCR was performed using primers 2X35S-CPMV 5′UTR.c (SEQ ID NO: 91) and ApaI-M prot.r (SEQ ID NO: 92):
TTGGAGAGG
TATTAAAATCTTAATAGGTTTTGATAAAAGCGAACGTGGG
using construct 745 (SEQ ID NO 75;
2. Assembly of Chaperone Expression Cassettes
Two heat shock protein (Hsp) expression cassettes were assembled. In a first cassette, expression of the Arabidopsis thaliana (ecotype Columbia) cytosolic HSP70 (Athsp70-1 in Lin et al. (2001) Cell Stress and Chaperones 6: 201-208) is controlled by a chimeric promoter combining elments of the alfalfa Nitrite reductase (Nir) and alfalfa Plastocyanin promoters (Nir/Plasto). A second cassette comprising the coding region of the alfalfa cytosolic HSP40 (MsJ1; Frugis et al. (1999) Plant Molecular Biology 40: 397-408) under the control of the chimeric Nir/Plasto promoter was also assembled.
An acceptor plasmid containing the alfalfa Nitrite reductase promoter (Nir), the GUS reporter gene and NOS terminator in plant binary vector was first assembled. Plasmid pNir3K51 (previously described in U.S. Pat. No. 6,420,548) was digested with HindIII and EcoRI. The resulting fragment was cloned into pCAMBIA2300 (Cambia, Canberra, Australia) digested by the same restriction enzyme to give pCAMBIA-Nir3K51.
Coding sequences for Hsp70 and Hsp40 were cloned separately in the acceptor plasmid pCAMBIANir3K51 by the PCR-based ligation method presented in Darveau et al. (Methods in Neuroscience 26:77-85 (1995)).
For Hsp40, Msj1 coding sequence (SEQ ID NO: 76;
A dual Hsp expression plasmid was assembled as follows. R860 (SEQ ID NO: 78;
3. Assembly of Other Expression Cassettes
An HcPro construct (35HcPro) was prepared as described in Hamilton et al. (2002). All clones were sequenced to confirm the integrity of the constructs. The plasmids were used to transform Agrobacteium tumefaciens (AGL1; ATCC, Manassas, Va. 20108, USA) by electroporation (Mattanovich et al., 1989). The integrity of all A. tumefaciens strains were confirmed by restriction mapping.
The coding sequence of p19 protein of tomato bushy stunt virus (TBSV) was linked to the alfalfa plastocyanin expression cassette by the PCR-based ligation method presented in Darveau et al. (Methods in Neuroscience 26: 77-85(1995)). In a first round of PCR, a segment of the plastocyanin promoter was amplified using primers Plasto-443c (SEQ ID NO: 5) and supP19-plasto.r (SEQ ID NO: 49) with construct 660 (SEQ ID NO: 53) as template. In parallel, another fragment containing the coding sequence of p19 was amplified with primers supP19-1c (SEQ ID NO: 50) and SupP19-SacI.r (SEQ ID NO: 51) using construct 35S:p19 as described in Voinnet et al. (The Plant Journal 33: 949-956 (2003)) as template. Amplification products were then mixed and used as template for a second round of amplification (assembling reaction) with primers Plasto-443c (SEQ ID NO: 5) and SupP19-SacI.r (SEQ ID NO: 51). The resulting fragment was digested with BamHI (in the plastocyanin promoter) and SacI (at the end of the p19 coding sequence) and cloned into construct number 660 (SEQ ID NO: 53;
Construct number 443 corresponds to pCAMBIA2300 (empty vetor).
TTAATCATCTTGAGAGAAAATGGAGAAAATAGTGCTTCTTCTTGC
TTGGAGAGG
TATTAAAATCTTAATAGGTTTTGATAAAAGCGAACGTG(
Agrobacterium strains used for expression of influenza
4. Preparation of Plant Biomass, Inoculum, Agroinfiltration, and Harvesting
Nicotiana benthamiana plants were grown from seeds in flats filled with a commercial peat moss substrate. The plants were allowed to grow in the greenhouse under a 16/8 photoperiod and a temperature regime of 25° C. day/20° C. night. Three weeks after seeding, individual plantlets were picked out, transplanted in pots and left to grow in the greenhouse for three additional weeks under the same environmental conditions. Prior to transformation, apical and axillary buds were removed at various times as indicated below, either by pinching the buds from the plant, or by chemically treating the plant
Agrobacteria transfected with each construct were grown in a YEB medium supplemented with 10 mM 2-[N-morpholino]ethanesulfonic acid (MES), 20 μM acetosyringone, 50 μg/ml kanamycin and 25 μg/ml of carbenicillin pH5.6 until they reached an OD600 between 0.6 and 1.6. Agrobacterium suspensions were centrifuged before use and resuspended in infiltration medium (10 mM MgCl2 and 10 mM MES pH 5.6). Syringe-infiltration was performed as described by Liu and Lomonossoff (2002, Journal of Virological Methods, 105:343-348). For vacuum-infiltration, A. tumefaciens suspensions were centrifuged, resuspended in the infiltration medium and stored overnight at 4° C. On the day of infiltration, culture batches were diluted in 2.5 culture volumes and allowed to warm before use. Whole plants of N. benthamiana or N. tabacumwere placed upside down in the bacterial suspension in an air-tight stainless steel tank under a vacuum of 20-40 Torr for 2-min. Following syringe or vacuum infiltration, plants were returned to the greenhouse for a 4-5 day incubation period until harvest. Unless otherwise specified, all infiltrations were performed as co-infiltration with AGL1/35S-HcPro in a 1:1 ratio, except for CPMV-HT cassette-bearing strains which were co-infiltrated with strain AGL1/R472 in a 1:1 ratio.
5. Leaf Sampling and Total Protein Extraction
Following incubation, the aerial part of plants was harvested, frozen at −80° C., crushed into pieces. Total soluble proteins were extracted by homogenizing (Polytron) each sample of frozen-crushed plant material in 3 volumes of cold 50 mM Tris pH 8, 0.15 M NaCl, 0.04% sodium metabisulfite and 1 mM phenylmethanesulfonyl fluoride. After homogenization, the slurries were centrifuged at 20,000 g for 20 min at 4° C. and these clarified crude extracts (supernatant) kept for analyses. The total protein content of clarified crude extracts was determined by the Bradford assay (Bio-Rad, Hercules, Calif.) using bovine serum albumin as the reference standard.
6. Protein Analysis and Immunoblotting
Protein concentrations were determined by the BCA protein assay (Pierce Biochemicals, Rockport Ill.). Proteins were separated by SDS-PAGE under reducing conditions and stained with Coomassie Blue. Stained gels were scanned and densitometry analysis performed using ImageJ Software (NIH).
Proteins from elution fraction from SEC were precipitated with acetone (Bollag et al., 1996), resuspended in ⅕ volume in equilibration/elution buffer and separated by SDS-PAGE under reducing conditions and electrotransferred onto polyvinylene difluoride (PVDF) membranes (Roche Diagnostics Corporation, Indianapolis, Ind.) for immunodetection. Prior to immunoblotting, the membranes were blocked with 5% skim milk and 0.1% Tween-20 in Tris-buffered saline (TBS-T) for 16-18 h at 4° C.
Immunoblotting was performed by incubation with a suitable antibody (Table 6), in 2 μg/ml in 2% skim milk in TBS-Tween 20 0.1%. Secondary antibodies used for chemiluminescence detection were as indicated in Table 4, diluted as indicated in 2% skim milk in TBS-Tween 20 0.1%. Immunoreactive complexes were detected by chemiluminescence using luminol as the substrate (Roche Diagnostics Corporation). Horseradish peroxidase-enzyme conjugation of human IgG antibody was carried out by using the EZ-Link Plus® Activated Peroxidase conjugation kit (Pierce, Rockford, Ill.). Whole inactivated virus (WIV), used as controls of detection for H1, H3 and B subtypes, were purchased from National Institute for Biological Standards and Control (NIBSC).
7. Clarification and Concentration Prior to SEC
To improve resolution and increase signal in elution fractions, extracts to be loaded on size exclusion chromatography, crude protein extracts were clarified and concentrated using the following method. Extracts were centrifuged at 70 000 g, 4° C. for 20 min and the pellet was washed twice by resuspension in 1 volume (compared to the initial extract volume) of extraction buffer (50 mM Tris pH 8, 0.15 M NaCl) and centrifugation at 70 000 g, 4° C. for 20 min. The resulting pellet was resuspended in ⅓ volume (compared to the initial extract volume) and proteins (including VLPs) were precipitated by the addition of 20% (w/v) PEG 3350 followed by incubation on ice for lh. Precipitated proteins were recovered by centrifugation at 10 000 g, 4° C., 20 min, and resuspended in 1/15 volume (compared to the initial extract volume) of extraction buffer. After complete resuspension of proteins, a final centrifugation at 20 000 g, 4° C., 5 min was performed to pellet insolubles and the clear supernatant was recovered.
8. Size Exclusion Chromatography of Protein Extract
Size exclusion chromatography (SEC) columns of 32 ml Sephacryl™ S-500 high resolution beads (S-500 HR: GE Healthcare, Uppsala, Sweden, Cat. No. 17-0613-10) were packed and equilibrated with equilibration/elution buffer (50 mM Tris pH8, 150 mM NaCl). One and a half millilitre of crude protein extract was loaded onto the column followed by an elution step with 45 mL of equilibration/elution buffer. The elution was collected in fractions of 1.5 mL relative protein content of eluted fractions was monitored by mixing 10 μL of the fraction with 200 μL of diluted Bio-Rad protein dye reagent (Bio-Rad, Hercules, Calif. The column was washed with 2 column volumes of 0.2N NaOH followed by 10 column volumes of 50 mM Tris pH8, 150 mM NaCl, 20% ethanol. Each separation was followed by a calibration of the column with Blue Dextran 2000 (GE Healthcare Bio-Science Corp., Piscataway, N.J., USA). Elution profiles of Blue Dextran 2000 and host soluble proteins were compared between each separation to ensure uniformity of the elution profiles between the columns used.
The RB subdomain of H5/Indo may be replaced by an RB subdomain of H1, H3 or B HA. The resulting chimeric HA provides an SDC H5/Indo to form VLPs and present the RB subdomain comprising immunogenic sites of H1, H3 or B. The H5/Indo RB subdomain may be inserted on an H1 stem (HI/NC).
Amino acids 1-92 of SEQ ID NO: 105 are an F′1+E1 domain of H5/Indo; amino acids 93-259 are the RB head domain of H3/Brisbane; amino acids 260-548 are the E2+F′2 domain of H5/Indo.
Amino acids 1-92 of SEQ ID NO: 106 are an F′1+E1 domain of H5/Indo; amino acids 93-276 are the RB head domain of B/Florida; amino acids 277-565 are the E2+F′2 domain of H5/Indo.
Amino acids 1-42 of SEQ ID NO: 107 are an N terminal F′1 domain of H5/Indo; amino acids 43-228 are the E1-RB-E2 head domain of H3/Brisbane; amino acids 229-507 are the F′2 domain of H5/Indo.
Amino acids 1-42 of SEQ ID NO: 108 are an N terminal F′1 domain of H5/Indo; amino acids 43-281 are the E1-RB-E2 head domain of B/Florida; amino acids 282-556 are the F′2 domain of H5/Indo.
Amino acids 1-42 of SEQ ID NO: 109 are an N terminal F′1 domain of H1/NC; amino acids 43-273 are the E1-RB-E2 head domain of H5/Indo; amino acids 274-548 are the F′2 domain of H1/NC.
The fusion points for the various chimeras were selected so as to be as close to (but not necessarily directly at) the N and C termini of the various subdomains—without wishing to be bound by theory, these fusions were selected so as to maximize the stability of the chimeric HA. For example, structure and sequence conservation is observed at the N-terminus of the RB subdomain (Ha et al. 2002, EMBO J. 21:865-875; which is incorporated herein by reference). A less variable region in the primary sequence is found at the C-F/Y-P triad located at approximately 15 amino acids before, in the E1 subdomain. This cysteine is involved in disulfide bridge #3, which is conserved among HAs (see
The E1-RB-E2 subdomains of a first influenza type were replaced by E1-RB-E2 subdomains of a second influenza type. Such an arrangement may present a greater number of amino acids of the second type at the surface of the H5-VLP. In this example, the HDC of H1, H3 or B was placed on an H5/Indo SDC, and an HDC of H5/Indo on an H1/NC SDC (Table 5).
The junction of the HDC was defined with a conserved cysteine residue (comprising disulfide bridge #6 of HA type A and #7 in HA type B). The junction of the HDC at the C-terminus of the E2 subdomain was defined with another conserved cysteine residue comprising disulfide bridge #6 (the second amino acid of the F′2 subdomain) of influenza type H1 or H3 on an SDC of H5/Indo or for influenza type H5 on an SDC of H1. For the influenza B chimera, the junction was established the connection at the first Cysteine comprising of disulfide bridge #4 (located 4 amino acids away on the F′2 subdomain, and conserved among the HAs). The resulting chimeras do not exhibit any alteration in disulfide bridge patterns—the H1/H3/H5 hybrid HAs will contain 6 disulfde bridges and the B hybrid will have 7 of them.
To combine the high accumulation level of VLPs from H5 A/Indonesia/5/05 with the antigenicity characteristics of H1 A/Brisbane/59/2007, chimeric hemagglutinins were designed comprising domains from H1 A/Brisbane/59/2007 fused to an H5 A/Indonesia/5/05 stem domain cluster. Expression cassettes for the expression of the H5/H1 hemagglutinin fusions are represented in
To compare the accumulation level of H5/H1 chimeric hemagglutinins with that of their native forms, Nicotiana benthamiana plants were infiltrated with AGL1/774, AGL1/691 and AGL1/690, and the leaves were harvested after a six-day incubation period. To determine the accumulation level of each HA form in the agroinfiltrated leaves, proteins were extracted from infiltrated leaf tissue and analyzed by Western blotting using anti-HA monoclonal antibodies. A unique band of approximately 75 kDa (
The fusion of the receptor-binding region from H1 A/Brisbane/59/2007 to the H5 A/Indonesia/5/05 backbone as a method of increasing accumulation of H1 antigen-presenting VLPs in plants was re-evaluated under the control of a strong CPMV-HT-based expression cassette. This fusion strategy was also compared to signal peptide replacement as mean of increasing accumulation level. Expression cassettes for the expression of the H5/H1 hemagglutinin fusions under CPMV-HT are represented in
Nicotiana benthamiana plants were infiltrated with AGL1/732, AGL1/733 or AGL1/734, and the leaves were harvested after a six-day incubation period. To determine the accumulation level of each HA form in the agroinfiltrated leaves, protein were first extracted from infiltrated leaf tissue and analyzed by Western blotting using anti-H1 (Brisbane) polyclonal antibodies. A unique band of approximately 75 kDa (
Use of an H1 backbone (from A/New Caledonia/20/99) for the presentation of H5 antigenic region was also evaluated. Expression cassettes for the expression of the H1/H5 hemagglutinin fusion are represented in
To compare the accumulation level of H1/H5 chimeric hemagglutinin with that of its native form, Nicotiana benthamiana plants were infiltrated with AGL1/660 and AGL1/696, and the leaves were harvested after a six-day incubation period. To determine the accumulation level of each HA form in the agroinfiltrated leaves, proteins were extracted from infiltrated leaf tissue and analyzed by Western blotting using anti-H5 (Indonesia) polyclonal antibodies. A unique band of approximately 75 kDa (
The fusion of the ectodamain from H3 A/Brisbane/10/2007 or B Florida/4/2006 to the transmembrane and cytoplasmic subdomains from H5 A/Indonesia/5/05 was evaluated as a strategy to present hemagglutinin antigenic regions from H3 and B strains while increasing their accumulation level in plants. Expression cassettes for the expression of the H5/H3 and H5/B hemagglutinin fusions are represented in
Accumulation level of H5/B chimeric hemagglutinin (745) was compared with that of native HA B (739) in Nicotiana benthamiana plants. Plants were infiltrated with AGL1/739 and AGL1/745, and the leaves were harvested after a six-day incubation period. To determine the accumulation level of each HA form in the agroinfiltrated leaves, proteins were first extracted from infiltrated leaf tissue and analyzed by Western blotting using anti-B (Florida) polyclonal antibodies. A unique band of approximately 75 kDa (
Similarly, accumulation level of H5/H3 chimeric hemagglutinin (737) was compared with that of its native form (736) in Nicotiana benthamiana plants. Plants were infiltrated with AGL1/736 and AGL1/737, and the leaves were harvested after a six-day incubation period. To determine the accumulation level of each HA form in the agroinfiltrated leaves, proteins were extracted from infiltrated leaf tissue and analyzed by Western blotting using anti-H3 (Brisbane) polyclonal antibodies. A unique band of approximately 75 kDa (
The production of VLPs from expression of the H5/B chimeric hemagglutinin (construct no. 745) was evaluated using size exclusion chromatography. Concentrated protein extracts from AGL1/745-infiltrated plants (1.5 mL) were fractionated by size exclusion chromatography (SEC) on Sephacryl™ S-500 HR columns (GE Healthcare Bio-Science Corp., Piscataway, N.J., USA). As shown in
Expression of Hsp40 and Hsp70 in plants and co-expression with influenza hemagglutinins is described in co-pending application PCT/CA2009/000032. Cytosolic Hsp70 and Hsp40 (construct number R870) of plant origin may also be co-expressed with chimeric hemagglutinins, to increase their accumulation level in plants. The co-expression may be performed by agroinfiltration of N. benthamiana plants with a bacterial suspension containing a mixture (1:1:1 ratio) of AGL1 bearing the cassette for the expression of the desired chimeric HA with AGL1/R870 and AGL1/35SHcPro.
Accumulation level of H5/B chimeric hemagglutinin (B/Flo HDC and SDC fused with an H5/Indo TDC) was evaluated in co-expression with HSP40 and HSP70 in Nicotiana benthamiana plants. Plants were infiltrated with AGL1/747, AGL1/747+AGL1/443 (empty vector) or AGL1/747+AGL1/R870 (HSP40/HSP70), and the leaves were harvested after a six-day incubation period. To determine the accumulation level of H5/B chimeric HA in the agroinfiltrated leaves, proteins were first extracted from infiltrated leaf tissue and analyzed by Western blotting using anti-B (Florida) polyclonal antibodies. A unique band of approximately 75 kDa (
All citations are herein incorporated by reference, as if each individual publication was specifically and individually indicated to be incorporated by reference herein and as though it were fully set forth herein. Citation of references herein is not to be construed nor considered as an admission that such references are prior art to the present invention.
In the description a number of terms are used extensively and definitions are provided to facilitate understanding of various aspects of the invention. Use of examples in the specification, including examples of terms, is for illustrative purposes only and is not intended to limit the scope and meaning of the embodiments of the invention herein. Numeric ranges are inclusive of the numbers defining the range. In the specification, the word “comprising” is used as an open-ended term, substantially equivalent to the phrase “including, but not limited to,” and the word “comprises” has a corresponding meaning.
One or more currently preferred embodiments of the invention have been described by way of example. The invention includes all embodiments, modifications and variations substantially as hereinbefore described and with reference to the examples and figures. It will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as defined in the claims. Examples of such modifications include the substitution of known equivalents for any aspect of the invention in order to achieve the same result in substantially the same way.
This application claims priority from U.S. Provisional Application No. 61/220,161 filed Jun. 24, 2009.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CA2010/000983 | 6/25/2010 | WO | 00 | 4/17/2012 |
| Number | Date | Country | |
|---|---|---|---|
| 61220161 | Jun 2009 | US |
