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The present invention relates to MERS-CoV, in particular to recombinant vesicular stomatitis viruses containing one or more MERS-CoV structural proteins, vaccines and prime-boost vaccines or immunogenic compositions against MERS-CoV.
Throughout this application, various references are cited in brackets to describe more fully the state of the art to which this invention pertains. The disclosure of these references is hereby incorporated by reference into the present invention.
MERS-CoV is an enveloped, single-stranded, positive-sense RNA virus, which belongs to the β-coronaviruses in the family of Coronaviridae (de Groot et al., 2013). It causes severe acute respiratory disease with symptoms of fever, cough, and shortness of breath in humans, and the fatality reaches as high as 30 to 40% (WHO, 2015). Since the known first cases of the disease in Jordan and Saudi Arabia in 2012, the disease spread to other middle-eastern countries and other parts of the world by travelers. The transmission of the MERS-CoV starts from the dromedary camels to humans, and from human to human transmission occurs through close contacts by the patient to care-takers such as hospital personnel, family members, and other people who are in close contact (Buchholz et al., 2013; Drosten et al., 2013). Considering the high fatality of the disease and the possibility of the epidemics in any parts of the world through human to human contacts, development of an efficient vaccine against MERS-CoV is needed to prevent the onset and the spread of the disease in human. The 3′ one-third of MERS-CoV genome encodes structural proteins such as spike (S) protein, envelope (E) protein, nucleocapsid protein (N), and membrane protein (M) (
An ideal MERS-CoV vaccine should induce completely protective immune responses, must be safe, relatively easy to administrate, and efficient for manufacturing. There is room for an improved MERS-CoV vaccine to meet all the criteria for an ideal MERS-CoV vaccine.
The Applicant has developed a system comprising a combination of vaccines that elicits a response against MERS-CoV.
In accordance with the present invention, a recombinant vesicular stomatitis virus (rVSV) carries at least one gene that encodes for a MERS-CoV structural protein or modifications thereof.
In one embodiment of the rVSV of the present invention, the MERS-CoV structural protein or modifications thereof includes one or more of a full-length spike (SF) protein of MERS-CoV, a receptor binding domain (RBD) of the SF protein, an envelope (E) protein of MERS-CoV, or a membrane (M) protein of MERS-CoV, or modifications thereof.
In another embodiment of the rVSV of the present invention, the at least one gene includes a gene that encodes for the RBD having a glycoprotein signal peptide at the NH2-terminus of the RBD. In one aspect, the glycoprotein signal peptide is a melittin signal peptide (msp).
In another embodiment of the rVSV of the present invention, the at least one gene includes a gene that encodes for the SF protein.
In another embodiment of the rVSV of the present invention, the at least one gene includes a gene that encodes for the E protein.
In another embodiment of the rVSV of the present invention, the at least one gene includes a gene that encodes for the RBD having a glycoprotein signal peptide at the NH2-terminus of the RBD, a gene that encodes for the E protein and a gene that encodes for the M protein. In one aspect, the glycoprotein signal peptide is a melittin signal peptide (msp).
In another embodiment of the rVSV of the present invention, the at least one gene includes a gene that encodes for the RBD having a glycoprotein signal peptide at the NH2-terminus of the RBD and a gene that encodes for the E protein. In one aspect the glycoprotein signal peptide is a melittin signal peptide (msp).
In another embodiment of the rVSV of the present invention, the rVSV is a replication competent rVSV of Indiana serotype(rVSVInd).
In another embodiment of the rVSV of the present invention, the rVSVInd include a mutant matrix protein gene.
In another embodiment of the rVSV of the present invention, the mutant rVSVInd matrix protein includes a GML mutation (rVSVInd-GML).
In another embodiment of the rVSV of the present invention, the rVSV is a replication competent rVSV of New Jersey serotype (rVSVNJ).
In another embodiment of the rVSV of the present invention, the rVSVNJ include a mutant matrix protein gene.
In another embodiment of the rVSV of the present invention, the rVSVNJ M protein includes a
GMM mutation (rVSVNJ-GMM) or a GMML mutation (rVSVNJ-GMML).
In another embodiment, the present invention is a MERS-CoV vaccine or immunogenic composition including a recombinant vesicular stomatitis virus (rVSV) of the present invention.
In one embodiment of the MERS-CoV vaccine or immunogenic composition of the present invention, the MERS-CoV vaccine or immunogenic composition comprises the rVSV carrying the gene that encodes for the full-length spike protein of the MERS-CoV, and wherein the rVSV is rVSVInd-GML, rVSVNJ-GMM or rVSVNJ-GMML.
In another embodiment of the MERS-CoV vaccine or immunogenic composition of the present invention, the MERS-CoV vaccine or immunogenic composition comprises the rVSV carrying the gene that encodes for the RBD having the glycoprotein signal peptide at the NH2 terminus of the RBD, and wherein the rVSV is rVSVInd-GML, rVSVNJ-GMM or rVSVNJ-GMML.
In another embodiment of the MERS-CoV vaccine or immunogenic composition of the present invention, the MERS-CoV vaccine or immunogenic composition comprises the rVSV carrying the gene that encodes for the E protein of the MERS-CoV, and wherein the rVSV is rVSVInd-GML, rVSVNJ-GMM or rVSVNJ-GMML.
In another embodiment of the MERS-CoV vaccine or immunogenic composition of the present invention, the MERS-CoV vaccine or immunogenic composition comprises the rVSV carrying the gene that encodes for the M protein of the MERS-CoV, and wherein the rVSV is rVSVInd-GML, rVSVNJ-GMM or rVSVNJ-GMML.
In another embodiment of the MERS-CoV vaccine or immunogenic composition of the present invention, the MERS-CoV vaccine or immunogenic composition comprises the rVSV carrying the gene that encodes for the having the glycoprotein signal peptide at the NH2-terminus of the RBD and the gene that encodes for the E protein, and wherein the rVSV is rVSVInd-GML, rVSVNJ-GMM or rVSVNJ-GMML.
In another embodiment of the MERS-CoV vaccine or immunogenic composition of the present invention, the MERS-CoV vaccine or immunogenic composition comprises the rVSV carrying the gene that encodes for the RBD having the glycoprotein signal peptide at the NH2 terminus of the RBD, the gene that encodes for the E protein of the MERS-CoV and the gene that encodes for the M protein of the MERS-CoV, and wherein the rVSV is rVSVInd-GML, rVSVNJ-GMM or rVSVNJ-GMML.
In another embodiment of the MERS-CoV vaccine or immunogenic composition of the present invention, the glycoprotein signal peptide is a honeybee melittin signal peptide.
In another embodiment, the present invention is a prime boost immunization combination against MERS-CoV including: (a) a prime vaccine or immunogenic composition comprising a replication competent recombinant vesicular stomatitis virus (rVSV) carrying at least one gene that encodes for a MERS-CoV structural protein or a modification thereof, and (b) a booster vaccine or immunogenic composition comprising a replication competent rVSV carrying the same at least one gene.
In one embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the MERS-CoV structural protein or modification thereof includes one or more of a full-length spike (SF) protein of MERS-CoV, a receptor binding domain (RBD) of the SF protein, an envelope (E) protein of MERS-CoV, or a membrane (M) protein of MERS-CoV, or any modifications thereof.
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the at least one gene includes a gene that encodes for the RBD having a glycoprotein signal peptide at the NH2-terminus of the RBD.
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the at least one gene includes a gene that encodes for the SF protein.
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the at least one gene includes a gene that encodes for the E protein.
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the at least one gene includes a gene that encodes for the RBD having a glycoprotein signal peptide at the NH2-terminus of the RBD, the E protein and the M protein.
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the at least one gene includes a gene that encodes for the RBD having a glycoprotein signal peptide at the NH2-terminus of the RBD and a gene that encodes for the E protein.
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the glycoprotein signal peptide is a honeybee melittin signal peptide.
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the rVSV of the prime vaccine or immunogenic composition and the rVSV of the booster vaccine or immunogenic composition are rVSV of the same serotype.
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the rVSV of the prime vaccine or immunogenic composition and the rVSV of the booster vaccine or immunogenic composition are rVSV of Indiana serotype (rVSVInd).
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the rVSV of the prime vaccine or immunogenic composition and the rVSV of the booster vaccine or immunogenic composition are rVSV of New Jersey serotype (rVSVNJ).
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the rVSV of the prime vaccine or immunogenic composition is Indiana serotype (VSVInd) and the rVSV of the booster vaccine or immunogenic composition is New Jersey serotype (VSVNJ).
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the rVSV of the prime vaccine or immunogenic composition is New Jersey serotype (rVSVNJ) and the rVSV of the booster vaccine or immunogenic composition is rVSV of Indiana serotype (rVSVInd).
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the rVSV of the prime vaccine and the rVSV of the booster vaccine include a mutant matrix protein gene of the rVSV.
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, when the rVSV is rVSVInd, the matrix protein of the rVSVInd includes a GML mutation (rVSVInd-GML).
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, when the rVSV is rVSVNJ, the matrix protein of the rVSVNJ includes a GMM mutation (rVSVNJ-GMM) or a GMML mutation (rVSVNJ-GMML).
In another embodiment of the prime boost immunization combination against MERS-CoV of the present invention, the rVSV of the prime vaccine or immunogenic composition and the rVSV of the booster vaccine or immunogenic composition include are codon optimized for expression in a human cell.
In another embodiment, the present invention is a method for inducing an immune response in a mammal against MERS-CoV, comprising administering to the mammal an effective amount of a vaccine or immunogenic composition of the present invention or administering the mammal a prime boost immunization platform of the present invention.
In one embodiment of the method for inducing an immune response in a mammal against MERS-CoV, the immune response includes a humoral and a cellular immune response.
In another embodiment, the present invention is a use of a MERS-CoV vaccine of the present invention for the prevention or treatment of a MERS-CoV infection.
In another embodiment, the present invention is a use of a combination medicament for the prevention or treatment of a MERS-CoV infection, the combination medicament comprising a prime boost immunization platform of the present invention.
In another embodiment, the present invention is a use of a rVSV of the present invention in the manufacture of a vaccine or immunogenic composition for the prevention or treatment of a MERS-CoV infection.
In accordance to the present invention, a recombinant receptor binding domain (RBD) of a spike protein of MERS-CoV includes or has a honeybee melittin signal peptide (msp) at the NH2 terminus of the RBD. In one embodiment, said recombinant RBD is encoded by a gene including SEQ ID NO: 20 or consisting essentially of SEQ ID NO: 20 or consisting of SEQ ID NO: 20.
The present invention will become more fully understood from the detailed description given herein and from the accompanying drawings, which are given by way of illustration only and do not limit the intended scope of the invention.
For convenience, the meaning of certain terms and phrases employed in the specification, examples, and appended claims are provided below. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
The articles “a” and “an” are used herein to refer to one or more than one (i.e., to at least one) of the grammatical object of the article.
The terms “animal” and “subject” as used herein includes all members of the animal kingdom including mammals, preferably humans.
The term “effective amount” as used herein means an amount effective and at dosages and for periods of time necessary to achieve the desired result.
“rVSV” is used to refer to a recombinant vesicular stomatitis virus.
The term “Indiana”, and “IND” are used to refer to the VSV serotype Indiana (VSVInd). The term “New Jersey”, and “NJ” are used to refer to the VSV serotype New Jersey (VSVNJ). In aspects of this invention, the VSVNJ is Hazelhurst strain (VSVNJ-H) or Ogden strain (VSVNJ-O).
“MWT” “M(WT)” are used to refer to VSV expressing a wild type matrix protein.
“G22E” is used to refer to a mutant matrix of VSVNJ having a glycine changed to a glutamic acid at position 22.
“G21E” is used to refer to a mutant matrix protein of VSVInd having a glycine changed to a glutamic acid at position 21.
“L110A” is used to refer to a mutant matrix protein of VSVNJ having a leucine changed to alanine at position 110.
“L111A” is used to refer to a mutant matrix protein protein of VSVInd having a leucine changed to alanine at position 111.
“L110F” is used to refer to a mutant matrix protein of VSVNJ having a leucine changed to phenylalanine at position 110.
“L111F” is used to refer to a mutant matrix protein of VSVInd having a leucine changed to phenylalanine at position 111.
“M51R” is used to refer to mutant matrix protein of the VSVInd having a methionine changed to an arginine at position 51.
“M48R+M51R” or “M48R/M51R” are used to refer to a mutant matrix protein of VSVNJ having a methionine changed to an arginine at positions 48 and 51 respectively.
“rVSVInd(GML)” is used to refer to VSVInd having the combined mutation G21E, M51R and one of L111A or L111F.
“rVSVNJ(GMM)” is used to refer to a VSVNJ having the combined mutation G22E, M48R/M51R.
“rVSVNJ(GMML)” is used to refer to a VSVNJ having the combined mutation G22E, M48R/M51R and one of L110A or L110F.
“SF” is a recombinant full length spike protein of MERS-CoV.
“S protein” is used to refer to the SF or partial length forms of the spike protein of MERS-CoV
“S1” is a recombinant S1 region or subunit of SF of MERS-CoV.
“S2” is a recombinant S2 region or subunit of SF of MERS-CoV.
“RBD” is used to refer to the receptor binding domain of the SF, found in S1 subunit.
“Partial length of the S protein” is used to refer to one or more of S1, S2 and RBD.
The term “protein” as used herein is defined as a chain of amino acid residues, usually having a defined sequence. As used herein the term protein is inclusive of the terms “peptides” and “proteins”. The terms also encompass an amino acid polymer that has been modified.
2. Overview
The present invention features rVSVs, immunization platforms, immunization regimens and medicaments and kits useful for inducing an immune response in a subject and preventing or treating MERS-CoV infection in a subject, wherein said rVSVs, platforms, regimens and medicaments and useful kits comprise a rVSV that carries one or more genes that encode for one or more structural proteins of MERS-CoV, including modifications of said one or more structural proteins to form pseudotype rVSVs that trigger efficient humoral immune responses against MERS-CoV.
The MERS-CoV gene can be genetically modified to encode a modified MERS-CoV structural protein that elevates glycoprotein synthesis and triggers efficient humoral immune response. In one embodiment, the MERS-CoV gene is genetically modified to produce modified structural proteins having a glycoprotein signal peptide at its N-terminus. Any glycoprotein signal peptide that allows the MERS-CoV structural protein to be glycosylated and involved in intracellular trafficking can be used, for example the honeybee melittin signal peptide. For example, a gene is genetically modified to produce RBD proteins having a honeybee melittin signal peptide (msp) at its N-terminus or to produce RBD proteins having the msp at its N-terminus, and the transmembrane domain and cytoplasmic tail of the VSV glycoprotein (Gtc) to form pseudotype VSVs that trigger efficient humoral immune responses against the RBD protein.
In one embodiment, the one or more MERS-CoV structural protein is one or more of a spike (S) protein, a receptor binding domain (RBD) of the S protein, an envelope (E) protein, or a membrane (M) protein of MERS-CoV, modifications of said S, RBD, E and M proteins.
The S protein of MERS-CoV can be a full-length spike (SF) protein or a partial length S protein. The partial length form of the S protein is one or more of S1 peptides of the SF protein, S2 peptides of the SF protein, the receptor binding domain of the SF protein (RBD) or any modifications thereof.
In embodiments, at least one of the S protein (SF or partial length S protein) and the E protein are modified with a glycoprotein signal peptide, such as the honeybee melittin signal peptide (msp), at the NH2-terminus of the at least one of the S protein (SF or partial length S protein) and the E protein, and/or the VSV G protein transmembrane domain and cystoplasmic tail (Gtc) at the COOH-terminus of the at least one of the S protein (SF or partial length S protein) and the E protein.
In one embodiment, the RBD gene is genetically modified to produce an RBD protein having a honeybee melittin signal peptide (msp) at its NH2-terminus to glycosylate the RBD that trigger efficient humoral immune responses against MERS-CoV.
3. Vaccines or Immunogenic Compositions of the Invention
The present invention further features vaccines or immunogenic compositions.
The present invention describes MERS-CoV vaccines or immunogenic compositions including a recombinant vesicular stomatitis virus (rVSV) that carries one or more genes that encode for at least one MERS-CoV structural protein, including at least one of the S protein (full or partial length forms), the E protein, of MERS-CoV, including modifications of said S, and E proteins. The S protein can be provided as a full-length spike (SF) protein, a S1 subunit of the SF protein, a S2 subunit of the SF protein, and/or a receptor binding domain (RBD) of the SF protein. In embodiments, the at least one of the S (SF or partial length S protein) and E proteins are modified with a glycoprotein signal peptide such as the honeybee melittin signal peptide (msp) at its NH2-terminus and/or a VSV G protein transmembrane domain and cystoplasmic tail (Gtc) at the COOH-terminus of the S (SF or partial length S protein) and/or E protein. In embodiments, the RBD protein is modified to include a glycoprotein signal peptide, such as the honeybee melittin signal peptide (msp) at its NH2- terminus to form pseudotype rVSVs that trigger efficient humoral immune responses against MERS-CoV. In embodiments, one or more genes that encode for the S (full or partial length forms), and E proteins and modifications therein are codon-optimized for expression in a human cell. The rVSV may be of Indiana serotype, New Jersey serotype or any other suitable VSV subtype.
The vaccines or immunogenic compositions of this invention may be provided as a prime-boost immunization combination against MERS-CoV. The rVSV of the prime vaccine or immunogenic composition may be of the same or different serotype as the rVSV of the boost vaccine or immunogenic composition. For example, both the prime and boost vaccines or immunogenic compositions are rVSVInd; or both the prime and boost vaccines or immunogenic compositions are rVSVNJ; or the rVSV of the prime vaccine or immunogenic composition is rVSVInd and the rVSV of the boost vaccine or immunogenic composition is rVSVNJ; or the rVSV of the prime vaccine or immunogenic composition is rVSVNJ and the rVSV of the boost vaccine or immunogenic composition is rVSVInd.
The vaccine or immunogenic compositions of the invention are suitable for administration to subjects in a biologically compatible form in vivo. The expression “biologically compatible form suitable for administration in vivo” as used herein means a form of the substance to be administered in which any toxic effects are outweighed by the therapeutic effects. The substances maybe administered to any animal or subject, preferably humans. The vaccines of the present invention may be provided as a lyophilized preparation. The vaccines of the present invention may also be provided as a solution that can be frozen for transportation. Additionally, the vaccines may contain suitable preservatives such as human albumin, bovine albumin, sucrose, glycerol or may be formulated without preservatives. If appropriate (i.e., no damage to the VSV in the vaccine), the vaccines may also contain suitable diluents, adjuvants and/or carriers.
The dose of the vaccine may vary according to factors such as the disease state, age, sex, and weight of the individual, and the ability of antibody to elicit a desired response in the individual. Dosage regime may be adjusted to provide the optimum therapeutic response. The dose of the vaccine may also be varied to provide optimum preventative dose response depending upon the circumstances.
4. Methods of Use
The present invention also features methods of inducing an immune response in a subject against MERS-CoV and/or preventing or treating a MERS-CoV infection in a subject comprising administering to the subject an effective amount of a vaccine or immunogenic composition or a combination of vaccines or immunogenic compositions of the present invention.
As such, in one embodiment, the present invention provides for a method for inducing an immune response in a subject to a MERS-CoV comprising the step (a) of administering to the subject an effective amount of a vaccine or immunogenic composition including a rVSV carrying one or more geneses that encode for one or more structural protein of MERS-CoV. In one embodiment, the method further comprises the step (b) of administering to the subject another vaccine or immunogenic composition comprising a rVSV carrying the same one or more genes that encode the same one or more structural proteins of MERS-CoV.
The rVSV of the vaccine or immunogenic composition of step (a), the priming vaccine or immunogenic composition, may be of the same or different serotype as the rVSV of the vaccine or immunogenic composition (b), the booster vaccine or immunogenic composition. For example, both the prime and boost vaccines or immunogenic compositions are rVSVInd; or both the prime and boost vaccines or immunogenic compositions are rVSVNJ; or the rVSV of the prime vaccine or immunogenic composition is rVSVInd and the rVSV of the boost vaccine or immunogenic composition is rVSVNJ; or the rVSV of the prime vaccine or immunogenic composition is rVSVNJ and the rVSV of the boost vaccine or immunogenic composition is rVSVInd.
In embodiments of the invention the methods for inducing an immune response in a mammal to a MERS-CoV and the methods for preventing or treating an infection caused by MERS-CoV may further comprise the step of (c) administering to the subject an effective amount of the vaccine or immunogenic composition of either step (a) or step (b). Step (c) may be administered to the subject more than one time over the course of inducing an immune response, preventing or treating.
Advantages
Advantages of the recombinant VSV-based platform technology of the present invention are first, a highly efficient prime-boost vaccination can be achieved with two antigenically distinct serotypes of rVSV vectors, because the vector immunity against the priming Indiana serotype (VSVInd) will not neutralize the boosting New Jersey serotype (VSVNJ) vector. Thus, VSVNJ carrying the same gene of interest as rVSVInd will provide maximum boost effects. A highly efficient prime-boost vaccination can also be achieved with the same serotype of rVSV vectors (i.e., both the prime and boost are rVSVInd or both the prime and boost are rVSVNJ), because The pseudotype VSVs carrying both VSV G protein and MERS-CoV spike protein on the surface of the virion can bind to either the low-density lipoprotein receptor (LDL-R) by VSV G protein and/or the human dipeptidyl peptidase 4 (hDPP-4) receptor by the spike protein of MERS-CoV. Thus, the vector immunity against one serotype of VSV may not block the infection of the same pseudotype VSV completely. This may provide boost effects.
Second, the genetically modified VSVInd M gene mutant (rVSVInd-GML) and genetically modified VSVNJ M gene mutant (rVSVNJ-GMM) vectors are completely safe, attenuated temperature sensitive mutants [22]. Third, rVSVInd-GML and rVSVNJ-GMM vectors carrying foreign genes replicate highly efficiently. Therefore, high titer rVSV-based vaccines are relatively easy to prepare. Fourth, both rVSVInd-GML and rVSVNJ-GMM vectors can accommodate a large-size foreign gene with up to 6,000 nucleotides, without decreasing the virus titer [24], and finally both serotypes of VSV have a very wide host range including humans.
The above disclosure generally describes the present invention. A more complete understanding can be obtained by reference to the following specific Examples. These Examples are described solely for purposes of illustration and are not intended to limit the scope of the invention. Changes in form and substitution of equivalents are contemplated as circumstances may suggest or render expedient. Although specific terms have been employed herein, such terms are intended in a descriptive sense and not for purposes of limitation.
The examples are described for the purposes of illustration and are not intended to limit the scope of the invention.
We have employed a genetically modified dual serotype of vesicular stomatitis virus (VSV) platform technology [22, 23] to develop vaccines against MERS-CoV.
We have developed MERS-CoV vaccines using temperature-sensitive avirulent rVSVInd-GML and rVSVNJ-GMM as vaccine vectors (
We recovered recombinant VSVs expressing MERS-CoV genes using the VSV reverse genetics system (
We also checked the secretion of the MERS-CoV proteins from three different cell lines infected with rVSVInd-GML-S, rVSVInd-GML-mspRBD, rVSVInd-GML-M, and rVSVInd-GML-E (
The concentrated culture media contains recombinant VSVs as well as the enveloped structures, which is made of MERS-CoV S, M, or E proteins. Recombinant VSV particles with randomly incorporated MERS-CoV S, E, and M proteins might be present in the concentrated culture media. In order to detect the MERS-CoV S, mspRBD, M, and E proteins, the culture media from the infected cells were collected at 22 hrs post-infection. The collected media was cleared off cell debris and was concentrated by the ultracentrifugation at 36,000 rpm for 2 hrs. MERS-CoV proteins in the pelleted material were detected by Western blot analysis using antibodies against S, M, and E proteins (
The Western blot analysis using the pelleted culture media indicated that MERS-CoV S, M, and E proteins were part of the sedimentable particles such as virus-like particles (VLP) and/or pseudotyped VSV particles. Therefore, we wanted to examine the presence of such particles which resemble the MERS-CoV by electron microscopy. We infected BHK21 cells separately with MOI of 6 of rVSVInd-GML-S, rVSVInd-GML-E, rVSVInd-GML-M, and rVSVInd-GML-E/M. The culture media was collected at 22 hrs post-infection. After clearing off cell debris, the culture media was concentrated by ultracentrifugation at 36,000 rpm for 2 hrs. The pelleted material was resuspended in PBS and was fixed in 0.1% glutaraldehyde at room temperature for an hour. The fixed samples were loaded on a formvar/carbon grid and was stained with 1% posphotungstic acid (PTA). All of the samples from BHK21 cells infected with rVSVInd-GML with S (
There is no currently available vaccine against MERS-CoV. Considering the high fatality of the disease, the development of an effective vaccine is required to prevent MERS. Expression of MERS-CoV E, M, and RBD(S) could generate virus-like particles (VLPs) and could induce neutralizing antibodies against MERS-CoV. We generated attenuated rVSVs of both Indiana and New Jersey serotypes expressing MERS-CoV structural proteins, RBD of Spike glycoprotein (S), Envelope protein (E), and Membrane protein (M). The rVSVs of the present invention are noncytolytic and avirulent. We examined the production of neutralization antibodies (nAb) against RBD, a receptor binding domain of Spike glycoprotein. We compared the efficiency of producing nAb by rVSV expressing RBD(S) alone or by rVSV expressing RBD(S), E, and M proteins. We checked the level of nAb against various MERS-CoV isolates. The following animal groups have been vaccinated with rVSV expressing MERS-CoV structural proteins, M, E, and RBD of S proteins. Rabbits were prime-immunized with rVSVInd-GML expressing MERS-CoV proteins and boos-immunized with rVSVNJ-GMM expressing MERS-CoV proteins (Table 1).
Group 1: As a negative control group, rabbits have been injected with 500 μl of phosphate buffered saline
Group 2: Rabbits have been injected with rVSV without MERS-CoV gene inserts. Each rabbit was prime immunized with 5×108 pfu/500 μl rVSVInd-GML, 3 weeks after priming, boost immunized with 5×108 pfu/500 μl rVSVNJ-GMM. Two weeks after boost-immunization, rabbits have been euthanized for serum collection
Groups 3: Each rabbit was prime immunized with 5×108 pfu/500 μl rVSVInd-GML MERS-CoV mspRBD(S), 3 weeks after priming, boost immunized with 5×108 pfu/500 μl rVSVNJ-GMM MERS-CoV mspRBD(S). Two weeks after boost-immunization, rabbits have been euthanized for serum collection.
Groups 4: Each rabbit were prime immunized with 5×108 pfu/500 μl rVSVInd-GML MERS-CoV mspRBD(S)/E, 3 weeks after priming, boost immunized with 5×108 pfu/500 μl rVSVNJ-GMM MERS-CoV RBD(S)/E. Two weeks after boost-immunization, rabbits have been euthanized for serum collection.
Group 5: Each rabbit was prime immunized with 5×108 pfu/500 μl rVSVInd-GML MERS-CoV RBD(S)/E/M, 3 weeks after priming, boost immunized with 5×108 pfu/500 μl rVSVNJ-GMM)-N MERS-CoV RBD(S)/E/M. Two weeks after boost-immunization, rabbits have been euthanized for serum collection.
We found rabbits immunized with 5×108 pfu/500 μl of rVSVInd-GML MERS-CoV mspRBD(S) followed by boost immunization with 5×108 pfu/500 μl rVSVNJ-GMM MERS-CoV mspRBD(S) induced high levels of antibodies (
The RBD specific antibodies were generated in rabbits vaccinated with rVSV expressing RBD(S) alone, rVSV expressing RBD(S) and E, and rVSV expressing RBD(S), E, and M (
We are now in position to carry out MERS-CoV challenge experiments. There has been advances made in generating small animal models for the MERS-CoV infection. Mice are not susceptible to MERS-CoV infections, however, when human dipeptidyl peptidase 4 (DPP-4), the cell surface receptor for MERS-CoV, were introduced into mouse genome as a transgene, mice became highly susceptible to MERS-CoV infection (Agrawal et al., 2015; Pascal et al., 2015). The infection in the human dipeptidyl peptidase 4 (hDPP-4) transgenic mice, hDPP-4 C57BL/C led to the replication of MERS-CoV in the lung and showed the typical symptoms of MERS-CoV infection, lethargy, rapid and shallow breathing, severe weight loss, and 40-100% mortality. This transgenic mouse is the perfect animal model to test the efficacy of our vaccines against MERS-CoV. We will vaccinate this hDPP-4 transgenic mice with our rVSVs expressing MERS-CoV structural proteins and challenge the vaccinated mice with wild type MERS-CoV and score the clinical signs and mortality of the vaccinated and unvaccinated control mice. We have a new State-Of-The-Art BSL3 Laboratory just opened at Western University where we can carry out the challenge studies using the hDPP-4 C57BL/C transgenic mice. We will use both rVSVInd and rVSVNJ. In prime-boost vaccines, the priming vaccine or immunogenic composition, are of the same or different serotype as the rVSV of the booster vaccine or immunogenic composition. For example, both the prime and boost vaccines or immunogenic compositions are rVSVInd; or both the prime and boost vaccines or immunogenic compositions are rVSVNJ; or the rVSV of the prime vaccine or immunogenic composition are rVSVInd and the rVSV of the boost vaccine or immunogenic composition are rVSVNJ; or the rVSV of the prime vaccine or immunogenic composition are rVSVNJ and the rVSV of the boost vaccine or immunogenic composition will be rVSVInd.
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It should be understood that although the present invention has been specifically disclosed by certain aspects, embodiments, and optional features, modification, improvement and variation of such aspects, embodiments, and optional features can be resorted to by those skilled in the art, and that such modifications, improvements and variations are considered to be within the scope of this invention.
The invention has been described broadly and generically herein. Each of the narrower species and subgeneric groupings falling within the generic disclosure also form part of the invention. In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognize that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group.
Filing Document | Filing Date | Country | Kind |
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PCT/CA2021/050514 | 4/16/2021 | WO |
Number | Date | Country | |
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63011028 | Apr 2020 | US |