Patent Application
20130149324
The present invention discloses a therapeutic vaccine against latent or active tuberculosis infection caused by the tuberculosis complex microorganisms (Mycobacterium tuberculosis, M. bovis, M. africanum). The invention furthermore discloses a multi-phase vaccine that can be administered either prophylactically or therapeutically as well as a diagnostic reagent for the detection of latent stages of tuberculosis.
Human tuberculosis caused by Mycobacterium tuberculosis (M. tuberculosis) is a severe global health problem, responsible for approx. 3 million deaths annually, according to the WHO. The worldwide incidence of new tuberculosis (TB) cases had been falling during the 1960s and 1970s but during recent decades this trend has markedly changed in part due to the advent of AIDS and the appearance of multidrug resistant strains of M. tuberculosis.
Organisms of the tuberculosis complex can cause a variety of diseases, but the commonest route of invasion is by inhalation of bacteria. This initiates an infection in the lung, which can ultimately spread to other parts of the body. Normally, this infection is restricted in growth by the immune system, so that the majority of infected individuals show few signs apart from cough and fever, which eventually abates. Approximately 30% of individuals are unable to contain the infection and they will develop primary disease, which in many cases will eventually prove fatal. However, it is believed that even those individuals who apparently control the infection remain infected, probably for the rest of their life. Certainly, individuals who have been healthy for years or even decades can suddenly develop tuberculosis, which has proven to be caused by the same organism they were infected with many years previously. M. tuberculosis and other organisms of the TB complex are unique in that the mycobacteria can evade the immune response and survive for long periods in a refractory non-replicating or slowly-replicating stage. This is referred to as latent TB and is at present a very significant global health problem that is estimated to affect approximately ⅓ of the world's population (Anon., 2001).
The course of a M. tuberculosis infection runs essentially through 3 phases, as illustrated in
The only vaccine presently available for clinical use is BCG, a vaccine whose efficacy remains a matter of controversy. Although BCG consistently performs well in animal models of primary infection, it has clearly failed to control the TB epidemic. Consistent with that, BCG vaccination appears to provide protection against pediatric TB (which is due to primary infection), while offering little or no protection against adult disease (which is often reactivation of latent infection acquired in childhood). It has also been shown that vaccination of individuals who are currently sensitized to mycobacteria or latently infected is ineffective. Thus, current vaccination strategies, while effective against primary disease, fail to activate immune responses that efficiently control surviving dormant bacteria.
At this point no vaccine has been developed that confers protection against reactivation whether given as a prophylactic vaccine prior to infection or as a therapeutic vaccine given to already latently infected individuals.
This makes the development of a new and improved vaccine against TB an urgent matter, which has been given a very high priority by the WHO. Many attempts to define protective mycobacterial substances have been made, and different investigators have reported increased resistance after experimental vaccination. However, these efforts have almost exclusively focused on the development of prophylactic vaccines for the prevention of disease (Doherty, 2002), and such vaccines have not been demonstrated to work if given in an immunotherapeutic fashion (J. Turner et al., Infect and Immunity, 2000, pp. 1706-1709).
It has been suggested that the transition of M. tuberculosis from primary infection to latency is accompanied by changes in gene expression (see, for example, Honer zu Bentrup, 2001, which is incorporated herein by reference). In vitro hypoxic culture conditions, which mimic the conditions of low oxygen tension and restricted nutrients found in the granuloma (the location of the latent infection), have been used to analyze changes in gene expression and a number of antigens have been found that are induced or markedly upregulated under these conditions e.g. the 16 kDa antigen α-crystalline (Boon, 2001, Monahan, 2001, Florczyk 2001, Sherman 2001, Manganelli, 2001, all of which are incorporated herein by reference) and Rv0569 as described in Rosenkrands, 2002, and which is described in WO0179274.
As noted in the references cited above, it is already known that some genes are upregulated under conditions that mimic latency. However, these are a limited subset of the total gene expression during latent infection. Moreover, as one skilled in the art will readily appreciate, expression of a gene is not sufficient to make it a good vaccine candidate. The only way to determine if a protein is recognized by the immune system during latent infection with M. tuberculosis is to produce the given protein and test it in an appropriate assay as described herein. Of the more than 200 hundred antigens known to be expressed during primary infection, and tested as vaccines, less than a half dozen have demonstrated significant potential. So far only one antigen has been shown to have any potential as a therapeutic vaccine (Lowrie, 1999). However this vaccine only worked if given as a DNA vaccine, an experimental technique so far not approved for use in humans. Moreover, the technique has proved controversial, with other groups claiming that vaccination using this protocol induces either non-specific protection or even worsens disease (J. Turner et al., Infect and Immunity, 2000, pp. 1706-1709).
What are needed are therapeutic vaccines that treat latent TB infection.
The present invention provides therapeutic vaccines based on molecules that are induced or upregulated under the conditions of low oxygen transmission and restricted nutrients found in the granuloma (i.e., the location of latent TB infection). These vaccines are therapeutic and contrast with prior art vaccines which are designed to elicit protective immune responses prior to infection (prophylactic vaccination) that are only effective against primary infection. The immune responses elicited are powerless against the latent stage of the disease, because the bacteria have changed the antigens that they produce so that in essence they have altered their appearance and the immune system can no longer recognize them. However, latency is a dynamic process, maintained by the immune response, as indicated by the dramatic increase in the risk of reactivation of TB after HIV infection or other events that compromise immunity. Therefore, an effective vaccination strategy to protect infected individuals (therapeutic vaccination) is possible, but only if it is directed against those antigens expressed in the latent stage.
Further, the present invention provides a multiphase vaccine that combines components with prophylactic and therapeutic activity. In contrast, existing TB vaccines do not result in sterilizing immunity but rather control the infection at a subclinical level (thereby resulting in the subsequent establishment of latent infection. After conventional prophylactic vaccination, the evasion of the primary immune response and the subsequent development of latent disease are probably at least in part due to the change in the antigenic profile of the invading bacteria. Thus, vaccinating with antigens associated with latent TB prevents or reduces the establishment of latent infection and therefore, a vaccine incorporating antigens expressed by the bacteria both in the first logarithmic growth phase and during latent disease improve long-term immunity when used as a prophylactic vaccine. A multiphase vaccine of the invention will also be efficient as a therapeutic vaccine thereby addressing the problem that the majority of the population in the third world who would receive a future TB vaccine could be already latently infected.
For a number of years, a major effort has been put into the identification of protective antigens for the development of novel prophylactic vaccines against TB and today a few antigens with demonstrated protective activity in prophylactic vaccines have been identified (e.g. ESAT-6, the 38 kDa antigen, Ag85A and Ag85B). Such molecules are useful components, which in combination with latency associated antigens such as α-crystalline, form a multiphase vaccine of the invention. Advantageously and in contrast to antigens in the art, the antigens described in the invention are incorporated in vaccines through the use of well-recognized vaccination technology, as demonstrated in provided examples.
Finally, the immunodominant antigens identified in this invention may be used as diagnostic reagents. Our group has abundantly demonstrated that antigens expressed by mycobacteria during the early stages of the infection, such as ESAT-6 (Early Secretory Antigen Target-6) are recognized in individuals who are in the process of developing primary TB, even though they are healthy at the time of diagnosis (Doherty 2002). However, the large numbers of contacts who are exposed, and almost certainly infected, remain negative to this antigen (Doherty 2002). Since those individuals latently infected remain healthy by making an immune response against the latent bacteria, they must be making an immune response to those antigens expressed by the latent bacteria. Thus, the antigens of the invention may also be used to diagnose latent infection and differentiate it from primary acute TB.
Other aspects and advantages of the invention will be readily apparent to one of skill in the art.
The invention is related to preventing, treating and detecting infections caused by species of the tuberculosis complex (Mycobacterium tuberculosis, M. bovis, M. africanum) by the use of a polypeptide comprising a M. tuberculosis antigen or an immunogenic portion or other variant thereof, or by the use of a DNA sequence encoding a M. tuberculosis antigen or an immunogenic portion or other variant thereof. The invention discloses a new therapeutic vaccine against tuberculosis comprising antigens induced during the latent stage of TB-infection. It also discloses a multiphase vaccine incorporating a combination of prophylactic and therapeutic antigens as well as diagnostic reagents for the detection of the latent stage of M. tuberculosis infection.
The present invention discloses the use of one or more polypeptides, nucleic acids encoding these polypeptides or fragments hereof, which polypeptides are expressed during the latent stage of the mycobacteria infection, which stage is characterized by low-oxygen tension in the microenvironment of the mycobacteria, for a therapeutic vaccine against tuberculosis.
The polypeptides comprises one or more amino acid sequences selected from
Preferably the immunogenic portions are selected from the group consisting of the sequences presented in Table 1 and the nucleic acid sequences are selected from the sequences presented in Table 2.
In another embodiment, the vaccine is a multiphase vaccine, where the polypeptides or fragments hereof are fused to other antigens with efficacy as prophylactic vaccines, where the fusion partner is selected from e.g. the group consisting of ESAT-6, TB10.4, CFP10, RD1-ORF5, RD1-ORF2, Rv1036, MPB64, MPT64, Ag85A, Ag85B (MPT59), MPB59, Ag85C, 19 kDa lipoprotein, MPT32.
The invention further discloses a therapeutic vaccine against tuberculosis comprising one or more polypeptides or fragments hereof, which polypeptides are expressed during the latent stage of the mycobacteria infection, which stage is characterized by low-oxygen tension in the microenvironment of the mycobacteria, or nucleic acids encoding these polypeptides.
Preferably, the therapeutic and multiphase vaccine comprises an additional delivery system selected from among, live recombinant vaccines, that is gene-modified organisms such as bacteria or viruses expressing mycobacteria genes, or immunogenic delivery systems such as, DNA vaccines, that is plasmids expressing genes or gene fragments for the proteins described above, or protein vaccines, that is the proteins themselves or synthetic peptides derived from the proteins themselves delivered in a delivery system such as an adjuvant.
The invention further discloses a therapeutic vaccine in which the amino acid sequence is lipidated so as to allow a self-adjuvanting effect of the polypeptide.
The invention also discloses a method for treating an animal, including a human being, with tuberculosis caused by virulent mycobacteria, e.g., by Mycobacterium tuberculosis, Mycobacterium africanum or Mycobacterium bovis, comprising administering to the animal the above-mentioned vaccine.
The invention also discloses a method for immunizing an animal, including a human being, against tuberculosis caused by virulent mycobacteria, e.g., by Mycobacterium tuberculosis, Mycobacterium africanum or Mycobacterium bovis, comprising administering to the animal the above mentioned vaccine.
In a still further embodiment, the invention discloses an immunogenic composition comprising a polypeptide as defined above, preferably in the form of a vaccine or in the form of a diagnostic reagent. The diagnostic reagent can be in the form of a skin test reagent (administered by the transcutaneous, subcutaneous or intradermal routes), a serological reagent or a reagent for stimulating a cell-mediated reaction.
In another embodiment, the invention discloses a nucleic acid fragment in isolated form which
The nucleic acid fragment is preferably a DNA fragment. The fragment can be used as a pharmaceutical.
In another embodiment, the invention discloses a vaccine comprising a nucleic acid fragment according to the invention, optionally inserted in a vector, the vaccine effecting in vivo expression of antigen by a human being or other mammal or animal, to whom the vaccine has been administered, the amount of expressed antigen being effective to confer substantially increased resistance to tuberculosis caused by virulent mycobacteria, e.g. by Mycobacterium tuberculosis, Mycobacterium africanum or Mycobacterium bovis, in an animal, including a human being.
In a further embodiment, the invention discloses the use of a nucleic acid fragment according to the invention for the preparation of a composition for the diagnosis of tuberculosis caused by virulent mycobacteria, e.g., by Mycobacterium tuberculosis, Mycobacterium africanum or Mycobacterium bovis, and the use of a nucleic acid fragment according to the invention for the preparation of a pharmaceutical composition for the vaccination against tuberculosis caused by virulent mycobacteria, e.g., by Mycobacterium tuberculosis, Mycobacterium africanum or Mycobacterium bovis.
In a still further embodiment, the invention discloses a vaccine for immunizing an human being or other mammal or animal, against tuberculosis caused by virulent mycobacteria, e.g. by Mycobacterium tuberculosis, Mycobacterium africanum or Mycobacterium bovis, comprising as the effective component a non-pathogenic microorganism, wherein at least one copy of a DNA fragment comprising a DNA sequence encoding a polypeptide as defined above has been incorporated into the microorganism (e.g., placed on a plasmid or in the genome) in a manner allowing the microorganism to express and optionally secrete the polypeptide.
In another embodiment, the invention discloses a replicable expression vector, which comprises a nucleic acid fragment according to the invention, and a transformed cell harboring at least one such vector.
In another embodiment, the invention discloses a method for producing a polypeptide as defined above, comprising
The invention also discloses a method of diagnosing tuberculosis caused by virulent mycobacteria, e.g. by Mycobacterium tuberculosis, Mycobacterium africanum or Mycobacterium bovis, in an animal, including a human being, comprising intradermally injecting, in the animal, a polypeptide as defined above or an immunogenic composition as defined above, a positive skin response at the location of injection being indicative of the animal having tuberculosis, and a negative skin response at the location of injection being indicative of the animal not having tuberculosis.
In another embodiment, the invention discloses a method for immunizing an animal, including a human being, against tuberculosis caused by virulent mycobacteria, e.g. by Mycobacterium tuberculosis, Mycobacterium africanum or Mycobacterium bovis, comprising administering to the animal the polypeptide as defined above, the immunogenic composition according to the invention, or the vaccine according to the invention.
Another embodiment of the invention discloses a monoclonal or polyclonal antibody, which is specifically reacting with a polypeptide as defined above in an immuno assay, or a specific binding fragment of said antibody. Preferably, said antibody is for use as a diagnostic reagent, e.g. for detection of mycobacteria antigens in sputum, urine or other body fluids of an infected animal, including a human being.
In a further embodiment the invention discloses a pharmaceutical composition that comprises an immunologically responsive amount of at least one member selected from the group consisting of:
In a still further embodiment the invention discloses a method for stimulating an immunogenic response in an animal which comprises administering to said animal an immunologically stimulating amount of at least one member selected from the group consisting of:
The vaccine, immunogenic composition and pharmaceutical composition according to the invention can be used therapeutically in a subject infected with a virulent mycobacterium combined with a prophylactic composition in a subject to prevent further infection with a virulent mycobacterium.
The invention also discloses a method for diagnosing previous or ongoing infection with a virulent mycobacterium, said method comprising
Finally, the invention discloses a method of diagnosing Mycobacterium tuberculosis infection in a subject comprising:
The word “polypeptide” in the present invention should have its usual meaning. That is an amino acid chain of any length, including a full-length protein, oligopeptides, short peptides and fragments thereof, wherein the amino acid residues are linked by covalent peptide bonds.
The polypeptide may be chemically modified by being glycosylated, by being lipidated (e.g. by chemical lipidation with palmitoyloxy succinimide as described by Mowat et al. 1991 or with dodecanoyl chloride as described by Lustig et al. 1976), by comprising prosthetic groups, or by containing additional amino acids such as e.g. a his-tag or a signal peptide.
Each polypeptide may thus be characterized by specific amino acids and be encoded by specific nucleic acid sequences. It will be understood that such sequences include analogues and variants produced by recombinant or synthetic methods wherein such polypeptide sequences have been modified by substitution, insertion, addition or deletion of one or more amino acid residues in the recombinant polypeptide and still be immunogenic in any of the biological assays described herein. Substitutions are preferably “conservative”. These are defined according to the following table. Amino acids in the same block in the second column and preferably in the same line in the third column may be substituted for each other. The amino acids in the third column are indicated in one-letter code.
A preferred polypeptide within the present invention is an immunogenic antigen from M. tuberculosis produced when the organism is subjected to the stresses associated with latent infection. Such antigen can for example also be derived from the M. tuberculosis cell and/or M. tuberculosis culture filtrate. Thus, a polypeptide comprising an immunogenic portion of one of the above antigens may consist entirely of the immunogenic portion, or may contain additional sequences. The additional sequences may be derived from the native M. tuberculosis antigen or be heterologous and such sequences may, but need not, be immunogenic.
Each polypeptide is encoded by a specific nucleic acid sequence. It will be understood that such sequences include analogues and variants hereof wherein such nucleic acid sequences have been modified by substitution, insertion, addition or deletion of one or more nucleic acids. Substitutions are preferably silent substitutions in the codon usage that will not lead to any change in the amino acid sequence, but may be introduced to enhance the expression of the protein.
In the present context the term “substantially pure polypeptide fragment” means a polypeptide preparation which contains at most 5% by weight of other polypeptide material with which it is natively associated (lower percentages of other polypeptide material are preferred, e.g. at most 4%, at most 3%, at most 2%, at most 1%, and at most ½%). It is preferred that the substantially pure polypeptide is at least 96% pure, i.e. that the polypeptide constitutes at least 96% by weight of total polypeptide material present in the preparation, and higher percentages are preferred, such as at least 97%, at least 98%, at least 99%, at least 99.25%, at least 99.5%, and at least 99.75%. It is especially preferred that the polypeptide fragment is in “essentially pure form”, i.e. that the polypeptide fragment is essentially free of any other antigen with which it is natively associated, i.e. free of any other antigen from bacteria belonging to the tuberculosis complex or a virulent mycobacterium. This can be accomplished by preparing the polypeptide fragment by means of recombinant methods in a non-mycobacterial host cell as will be described in detail below, or by synthesizing the polypeptide fragment by the well-known methods of solid or liquid phase peptide synthesis, e.g. by the method described by Merrifield, 1963, or variations thereof.
By the term “virulent mycobacterium” is understood a bacterium capable of causing the tuberculosis disease in an animal or in a human being. Examples of virulent mycobacteria include but are not limited to M. tuberculosis, M. africanum, and M. bovis. Examples of relevant animals are cattle, possums, badgers and kangaroos.
By “a TB patient” is understood an individual with culture or microscopically proven infection with virulent mycobacteria, and/or an individual clinically diagnosed with TB and who is responsive to anti-TB chemotherapy. Culture, microscopy and clinical diagnosis of TB are well known by any person skilled in the art.
By the term “PPD-positive individual” is understood an individual with a positive Mantoux test or an individual where PPD induces a positive in vitro recall response determined by release of IFN-γ.
By “a latently infected individual” is understood an individual, who has been infected by a virulent mycobacterium, e.g. M. tuberculosis, but shows no sign of active tuberculosis. It is likely that individuals who have been vaccinated, e.g. by BCG, or treated for TB may still retain the mycobacteria within their bodies, although this is currently impossible to prove since such individuals would be expected to be positive if tested for PPD reactivity. Nonetheless, in its most accurate sense, “latently-infected” may be used to describe any individual who has M. tuberculosis residing in their tissues but who is not clinically ill.
By the term “delayed type hypersensitivity reaction” (DTH) is understood a T-cell mediated inflammatory response elicited after the injection of a polypeptide into, or application to, the skin, said inflammatory response appearing 72-96 hours after the polypeptide injection or application.
By the term “IFN-γ” is understood interferon-gamma. The measurement of IFN-γ is used as an indication of an immunological response.
By the terms “nucleic acid fragment” and “nucleic acid sequence” are understood any nucleic acid molecule including DNA, RNA, LNA (locked nucleic acids), PNA, RNA, dsRNA and RNA-DNA-hybrids. Also included are nucleic acid molecules comprising non-naturally occurring nucleosides. The term includes nucleic acid molecules of any length e.g. from 10 to 10000 nucleotides, depending on the use. When the nucleic acid molecule is for use as a pharmaceutical, e.g. in DNA therapy, or for use in a method for producing a polypeptide according to the invention, a molecule encoding at least one epitope is preferably used, having a length from about 18 to about 1000 nucleotides, the molecule being optionally inserted into a vector. When the nucleic acid molecule is used as a probe, as a primer or in antisense therapy, a molecule having a length of 10-100 is preferably used. According to the invention, other molecule lengths can be used, for instance a molecule having at least 12, 15, 21, 24, 27, 30, 33, 36, 39, 42, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500 or 1000 nucleotides (or nucleotide derivatives), or a molecule having at most 10000, 5000, 4000, 3000, 2000, 1000, 700, 500, 400, 300, 200, 100, 50, 40, 30 or 20 nucleotides (or nucleotide derivatives).
The term “stringent” when used in conjunction with hybridization conditions is as defined in the art, i.e. the hybridization is performed at a temperature not more than 15-20° C. under the melting point Tm, cf. Sambrook et al, 1989, pages 11.45-11.49. Preferably, the conditions are “highly stringent”, i.e. 5-10° C. under the melting point Tm.
Throughout this specification, unless the context requires otherwise, the word “comprise”, or variations thereof such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element or integer or group of elements or integers but not the exclusion of any other element or integer or group of elements or integers.
The term “sequence identity” indicates a quantitative measure of the degree of homology between two amino acid sequences of equal length or between two nucleotide sequences of equal length. The two sequences to be compared must be aligned to best possible fit allowing the insertion of gaps or alternatively, truncation at the ends of the protein sequences. The sequence identity can be calculated as
wherein Ndif is the total number of non-identical residues in the two sequences when aligned and wherein Nref is the number of residues in one of the sequences. Hence, the DNA sequence AGTCAGTC [SEQ ID NO: 184] will have a sequence identity of 75% with the sequence AATCAATC, SEQ ID NO: 185 (Ndif=2 and Nref=8). A gap is counted as non-identity of the specific residue(s), i.e. the DNA sequence AGTGTC [SEQ ID NO: 186] will have a sequence identity of 75% with the DNA sequence AGTCAGTC, SEQ ID NO: 187, (Ndif=2 and Nref=8). Sequence identity can alternatively be calculated by the BLAST program e.g. the BLASTP program (Pearson, 1988, or online through the NIH website). In one aspect of the invention, alignment is performed with the sequence alignment method ClustalW with default parameters as described by Thompson J., et al. 1994 and as available through online sources.
A preferred minimum percentage of sequence identity is at least 80%, such as at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, and at least 99.5%.
In a preferred embodiment of the invention, the polypeptide comprises an immunogenic portion of the polypeptide, such as an epitope for a B-cell or T-cell. The immunogenic portion of a polypeptide is a part of the polypeptide, which elicits an immune response in an animal or a human being, and/or in a biological sample determined by any of the biological assays described herein. The immunogenic portion of a polypeptide may be a T-cell epitope or a B-cell epitope. Immunogenic portions can be related to one or a few relatively small parts of the polypeptide, they can be scattered throughout the polypeptide sequence or be situated in specific parts of the polypeptide. For a few polypeptides, epitopes have even been demonstrated to be scattered throughout the polypeptide covering the full sequence (Ravn et al 1999). In order to identify relevant T-cell epitopes which are recognized during an immune response, it is possible to use overlapping oligopeptides for the detection of MHC class II epitopes, preferably synthetic, having a length of e.g. 20 amino acid residues derived from the polypeptide. These peptides can be tested in biological assays (e.g. the IFN-γ assay as described herein) and some of these will give a positive response (and thereby be immunogenic) as evidence for the presence of a T cell epitope in the peptide. For the detection of MHC class I epitopes it is possible to predict peptides that will bind (Stryhn et al. 1996) and hereafter produce these peptides synthetic and test them in relevant biological assays, e.g. the IFN-γ assay as described herein. The peptides preferably having a length of, e.g., 8 to 11 amino acid residues derived from the polypeptide. B-cell epitopes can be determined by analyzing the B cell recognition to overlapping peptides covering the polypeptide of interest as, e.g., described in Harboe et al 1998.
Although the minimum length of a T-cell epitope has been shown to be at least 6 amino acids, it is normal that such epitopes are constituted of longer stretches of amino acids. Hence, it is preferred that the polypeptide fragment of the invention has a length of at least 7 amino acid residues, such as at least 8, at least 9, at least 10, at least 12, at least 14, at least 16, at least 18, at least 20, at least 22, at least 24, and at least 30 amino acid residues. Hence, in important embodiments of the inventive method, it is preferred that the polypeptide fragment has a length of at most 50 amino acid residues, such as at most 40, 35, 30, 25, and 20 amino acid residues. It is expected that the peptides having a length of from 10 to 20 amino acid residues will prove to be most efficient as MHC class II epitopes and therefore especially preferred lengths of the polypeptide fragment used in the inventive method are 18, such as 15, 14, 13, 12 and even 11 amino acid residues. It is expected that the peptides having a length of from 7 to 12 amino acid residues will prove to be most efficient as MHC class I epitopes and therefore especially preferred lengths of the polypeptide fragment used in the inventive method are 11, such as 10, 9, 8 and even 7 amino acid residues.
Immunogenic portions of polypeptides may be recognized by a broad part (high frequency) or by a minor part (low frequency) of the genetically heterogeneous human population. In addition some immunogenic portions induce high immunological responses (dominant), whereas others induce lower, but still significant, responses (subdominant). High frequency or low frequency can be related to the immunogenic portion binding to widely distributed MHC molecules (HLA type) or even by multiple MHC molecules (Sinigaglia, 1988, Kilgus, 1991).
In the context of providing candidate molecules for a new vaccine against tuberculosis, the subdominant epitopes are however as relevant as are the dominant epitopes since it has been shown (Olsen, 2000) that such epitopes can induce protection regardless of the fact that they are not as strongly or broadly recognized.
A common feature of the polypeptides of the invention is their capability to induce an immunological response as illustrated in the examples. It is understood that a variant of a polypeptide of the invention produced by substitution, insertion, addition or deletion may also be immunogenic as determined by any of the assays described herein.
An immune individual is defined as a person or an animal, which has cleared or controlled an infection with virulent mycobacteria or has received a vaccination with M. bovis BCG.
The immune response may be monitored by one of the following methods:
In general, M. tuberculosis antigens, and DNA sequences encoding such antigens, may be prepared using any one of a variety of procedures.
They may be purified as native proteins from the M. tuberculosis cell or culture filtrate by procedures such as those described above. Immunogenic antigens may also be produced recombinantly using a DNA sequence encoding the antigen, which has been inserted into an expression vector and expressed in an appropriate host. Examples of host cells are E. coli. The polypeptides or immunogenic portion hereof can also be produced synthetically having fewer than about 100 amino acids, and generally fewer than 50 amino acids and may be generated using techniques well known to those ordinarily skilled in the art, such as commercially available solid-phase techniques where amino acids are sequentially added to a growing amino acid chain.
In the construction and preparation of plasmid DNA encoding the polypeptide as defined for DNA vaccination a host strain such as E. coli can be used. Plasmid DNA can then be prepared from cultures of the host strain carrying the plasmid of interest, and purified using e.g. the Qiagen Giga-Plasmid column kit (Qiagen, Santa Clarita, Calif., USA) including an endotoxin removal step. It is preferred that plasmid DNA used for DNA vaccination is endotoxin free.
The immunogenic polypeptides may also be produced as fusion proteins, by which methods superior characteristics of the polypeptide of the invention can be achieved. For instance, fusion partners that facilitate export of the polypeptide when produced recombinantly, fusion partners that facilitate purification of the polypeptide, and fusion partners which enhance the immunogenicity of the polypeptide fragment of the invention are all interesting possibilities. Therefore, the invention also pertains to a fusion polypeptide comprising at least one polypeptide or immunogenic portion defined above and at least one fusion partner. The fusion partner can, in order to enhance immunogenicity, be another polypeptide derived from M. tuberculosis, such as of a polypeptide fragment derived from a bacterium belonging to the tuberculosis complex, such as ESAT-6, TB10.4, CFP10, RD1-ORF5, RD1-ORF2, Rv1036, MPB64, MPT64, Ag85A, Ag85B (MPT59), MPB59, Ag85C, 19 kDa lipoprotein, MPT32 and alpha-crystalline, or at least one T-cell epitope of any of the above mentioned antigens (Skjøt et al 2000; Danish Patent application PA 2000 00666; Danish Patent application PA 1999 01020; U.S. patent application Ser. No. 09/505,739; Rosenkrands et al 1998; Nagai et al 1991). The invention also pertains to a fusion polypeptide comprising mutual fusions of two or more of the polypeptides (or immunogenic portions thereof) of the invention.
Other fusion partners, which could enhance the immunogenicity of the product, are lymphokines such as IFN-γ, IL-2 and IL-12. In order to facilitate expression and/or purification, the fusion partner can e.g. be a bacterial fimbrial protein, e.g. the pilus components pilin and papA; protein A; the ZZ-peptide (ZZ-fusions are marketed by Pharmacia in Sweden); the maltose binding protein; glutathione S-transferase; β-galactosidase; or poly-histidine. Fusion proteins can be produced recombinantly in a host cell, which could be E. coli, and it is a possibility to induce a linker region between the different fusion partners.
Other interesting fusion partners are polypeptides, which are lipidated so that the immunogenic polypeptide is presented in a suitable manner to the immune system. This effect is e.g. known from vaccines based on the Borrelia burgdorferi OspA polypeptide as described in e.g. WO 96/40718 A or vaccines based on the Pseudomonas aeruginosa OprI lipoprotein (Cote-Sierra J 1998). Another possibility is N-terminal fusion of a known signal sequence and an N-terminal cystein to the immunogenic polypeptide. Such a fusion results in lipidation of the immunogenic polypeptide at the N-terminal cystein, when produced in a suitable production host.
Another part of the invention pertains to a vaccine composition comprising a polypeptide (or at least one immunogenic portion thereof) or fusion polypeptide according to the invention. In order to ensure optimum performance of such a vaccine composition it is preferred that it comprises an immunologically and pharmaceutically acceptable carrier, vehicle or adjuvant.
An effective vaccine, wherein a polypeptide of the invention is recognized by the animal, will in an animal model be able to decrease bacterial load in target organs, prolong survival times and/or diminish weight loss after challenge with a virulent Mycobacterium, compared to non-vaccinated animals
Suitable carriers are selected from the group consisting of a polymer to which the polypeptide(s) is/are bound by hydrophobic non-covalent interaction, such as a plastic, e.g. polystyrene, or a polymer to which the polypeptide(s) is/are covalently bound, such as a polysaccharide, or a polypeptide, e.g. bovine serum albumin, ovalbumin or keyhole limpet haemocyanin. Suitable vehicles are selected from the group consisting of a diluent and a suspending agent. The adjuvant is preferably selected from the group consisting of dimethyldioctadecylammonium bromide (DDA), Quil A, poly I:C, aluminum hydroxide, Freund's incomplete adjuvant, IFN-γ, IL-2, IL-12, monophosphoryl lipid A (MPL), Trehalose Dimycolate (TDM), Trehalose Dibehenate and muramyl dipeptide (MDP).
Preparation of vaccines which contain peptide sequences as active ingredients is generally well understood in the art, as exemplified by U.S. Pat. Nos. 4,608,251; 4,601,903; 4,599,231 and 4,599,230, all incorporated herein by reference.
Other methods of achieving adjuvant effect for the vaccine include use of agents such as aluminum hydroxide or phosphate (alum), synthetic polymers of sugars (Carbopol), aggregation of the protein in the vaccine by heat treatment, aggregation by reactivating with pepsin treated (Fab) antibodies to albumin, mixture with bacterial cells such as C. parvum or endotoxins or lipopolysaccharide components of gram-negative bacteria, emulsion in physiologically acceptable oil vehicles such as mannide mono-oleate (Aracel A) or emulsion with 20 percent solution of a perfluorocarbon (Fluosol-DA) used as a block substitute may also be employed. Other possibilities involve the use of immune modulating substances such as cytokines or synthetic IFN-γ inducers such as poly I:C in combination with the above-mentioned adjuvants.
Another interesting possibility for achieving adjuvant effect is to employ the technique described in Gosselin et al., 1992 (which is hereby incorporated by reference herein). In brief, a relevant antigen such as an antigen of the present invention can be conjugated to an antibody (or antigen binding antibody fragment) against the Fcγ receptors on monocytes/macrophages.
The vaccines are administered in a manner compatible with the dosage formulation, and in such amount as will be therapeutically effective and immunogenic. The quantity to be administered depends on the subject to be treated, including, e.g., the capacity of the individual's immune system to mount an immune response, and the degree of protection desired. Suitable dosage ranges are of the order of several hundred micrograms active ingredient per vaccination with a preferred range from about 0.1 μg to 1000 μg, such as in the range from about 1 μg to 300 μg, and especially in the range from about 10 μg to 50 μg. Suitable regimens for initial administration and booster shots are also variable but are typified by an initial administration followed by subsequent inoculations or other administrations.
The manner of application may be varied widely. Any of the conventional methods for administration of a vaccine are applicable. These are believed to include oral application on a solid physiologically acceptable base or in a physiologically acceptable dispersion, parenterally, by injection or the like. The dosage of the vaccine will depend on the route of administration and will vary according to the age of the person to be vaccinated and, to a lesser degree, the size of the person to be vaccinated.
The vaccines are conventionally administered parenterally, by injection, for example, either subcutaneously or intramuscularly. Additional formulations which are suitable for other modes of administration include suppositories and, in some cases, oral formulations. For suppositories, traditional binders and carriers may include, for example, polyalkylene glycols or triglycerides; such suppositories may be formed from mixtures containing the active ingredient in the range of 0.5% to 10%, preferably 1-2%. Oral formulations include such normally employed excipients as, for example, pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, magnesium carbonate, and the like. These compositions take the form of solutions, suspensions, tablets, pills, capsules, sustained release formulations or powders and advantageously contain 10-95% of active ingredient, preferably 25-70%.
In many instances, it will be necessary to have multiple administrations of the vaccine. Especially, vaccines can be administered to prevent an infection with virulent mycobacteria, a prophylactic vaccine, and/or to treat established mycobacterial infection, a therapeutic vaccine. When administered to prevent an infection, the vaccine is given prophylactically, before definitive clinical signs, diagnosis or identification of an infection TB are present. Since the current vaccine BCG appears to induce an effective, but short-lived immune response, prophylactic vaccines may also be designed to be used as booster vaccines. Such booster vaccines are given to individuals who have previously received a vaccination, with the intention of prolonging the period of protection. In instances where the individual has already become infected or is suspected to have become infected, the previous vaccination may have provided sufficient immunity to prevent primary disease, but as discussed previously, boosting this immune response will not help against the latent infection. In such a situation, the vaccine will necessarily have to be a therapeutic vaccine designed for efficacy against the latent stage of infection. A combination of a prophylactic vaccine and a therapeutic vaccine, which is active against both primary and latent infection, constitutes a multiphase vaccine.
Due to genetic variation, different individuals may react with immune responses of varying strength to the same polypeptide. Therefore, the vaccine according to the invention may comprise several different polypeptides in order to increase the immune response. The vaccine may comprise two or more polypeptides or immunogenic portions, where all of the polypeptides are as defined above, or some but not all of the peptides may be derived from virulent mycobacteria. In the latter example, the polypeptides not necessarily fulfilling the criteria set forth above for polypeptides may either act due to their own immunogenicity or merely act as adjuvants.
The vaccine may comprise 1-20, such as 2-20 or even 3-20 different polypeptides or fusion polypeptides, such as 3-10 different polypeptides or fusion polypeptides.
The invention also pertains to a method for immunizing an animal, including a human being, against TB caused by virulent mycobacteria, comprising administering to the animal the polypeptide of the invention, or a vaccine composition of the invention as described above, or a living vaccine described above.
The invention also pertains to a method for producing an immunologic composition according to the invention, the method comprising preparing, synthesizing or isolating a polypeptide according to the invention, and solubilizing or dispersing the polypeptide in a medium for a vaccine, and optionally adding other M. tuberculosis antigens and/or a carrier, vehicle and/or adjuvant substance.
The nucleic acid fragments of the invention may be used for effecting in vivo expression of antigens, i.e. the nucleic acid fragments may be used in so-called DNA vaccines as reviewed in Ulmer et al 1993, which is included by reference.
Hence, the invention also relates to a vaccine comprising a nucleic acid fragment according to the invention, the vaccine effecting in vivo expression of antigen by an animal, including a human being, to whom the vaccine has been administered, the amount of expressed antigen being effective to confer substantially increased resistance to infections caused by virulent mycobacteria in an animal, including a human being.
The above mentioned definitions and distinctions of prophylactic-, booster-, therapeutic- and multiphase vaccines also applies for DNA vaccines
The efficacy of such a DNA vaccine can possibly be enhanced by administering the gene encoding the expression product together with a DNA fragment encoding a polypeptide that has the capability of modulating an immune response.
One possibility for effectively activating a cellular immune response for a vaccine can be achieved by expressing the relevant antigen in a vaccine in a non-pathogenic microorganism or virus. Well-known examples of such microorganisms are Mycobacterium bovis BCG, Salmonella and Pseudomona and examples of viruses are Vaccinia Virus and Adenovirus.
Therefore, another important aspect of the present invention is an improvement of the living BCG vaccine presently available, wherein one or more copies of a DNA sequence encoding one or more polypeptide as defined above has been incorporated into the genome of the micro-organism in a manner allowing the micro-organism to express and secrete the polypeptide. The incorporation of more than one copy of a nucleotide sequence of the invention is contemplated to enhance the immune response.
Another possibility is to integrate the DNA encoding the polypeptide according to the invention in an attenuated virus such as the vaccinia virus or Adenovirus (Rolph et al 1997). The recombinant vaccinia virus is able to replicate within the cytoplasma of the infected host cell and the polypeptide of interest can therefore induce an immune response, which is envisioned to induce protection against TB.
The invention also relates to the use of a polypeptide or nucleic acid of the invention for use as therapeutic vaccines as have been described by D. Lowrie (Lowrie, 1999) using DNA vaccine encoding HSP65 from M. leprae. Antigens with therapeutic properties may be identified based on their ability to diminish the severity of M. tuberculosis infection in experimental animals or prevent reactivation of previous infection, when administered as a vaccine. The composition used for therapeutic vaccines can be prepared as described above for vaccines.
The invention also relates to a method of diagnosing latent TB caused by a virulent mycobacterium in an animal, including a human being, comprising intradermally injecting, in the animal, a polypeptide according to the invention, a positive skin response at the location of injection being indicative of the animal having TB, and a negative skin response at the location of injection being indicative of the animal not having TB.
When diagnosis of latent infection with virulent mycobacteria is the aim, a blood sample comprising mononuclear cells (i.e. T-lymphocytes) from a patient is contacted with a sample of one or more polypeptides of the invention. This contacting can be performed in vitro and a positive reaction could e.g. be proliferation of the T-cells or release of cytokines such as IFN-γ into the extracellular phase. It is also conceivable to contact a serum sample from a subject with a polypeptide of the invention, the demonstration of a binding between antibodies in the serum sample and the polypeptide being indicative of previous or ongoing infection.
The invention therefore also relates to an in vitro method for diagnosing latent infection in an animal or a human being with a virulent mycobacterium, the method comprising providing a blood sample from the animal or human being, and contacting the sample from the animal with the polypeptide of the invention, a significant release into the extracellular phase of at least one cytokine by mononuclear cells in the blood sample being indicative of the animal being sensitized. A positive response being a response more than release from a blood sample derived from a patient without the TB diagnosis plus two standard deviations. The invention also relates to the in vitro method for diagnosing ongoing or previous sensitization in an animal or a human being with a virulent mycobacterium, the method comprising providing a blood sample from the animal or human being, and by contacting the sample from the animal with the polypeptide of the invention demonstrating the presence of antibodies recognizing the polypeptide of the invention in the serum sample.
The immunogenic composition used for diagnosing may comprise 1-20, such as 2-20 or even 3-20 different polypeptides or fusion polypeptides, such as 3-10 different polypeptides or fusion polypeptides.
The nucleic acid probes encoding the polypeptide of the invention can be used in a variety of diagnostic assays for detecting the presence of pathogenic organisms in a given sample.
A method of determining the presence of mycobacterial nucleic acids in an animal, including a human being, or in a sample, comprising administering a nucleic acid fragment of the invention to the animal or incubating the sample with the nucleic acid fragment of the invention or a nucleic acid fragment complementary thereto, and detecting the presence of hybridized nucleic acids resulting from the incubation (by using the hybridization assays which are well-known in the art), is also included in the invention. Such a method of diagnosing TB might involve the use of a composition comprising at least a part of a nucleotide sequence as defined above and detecting the presence of nucleotide sequences in a sample from the animal or human being to be tested which hybridize with the nucleic acid fragment (or a complementary fragment) by the use of PCR technique.
A monoclonal or polyclonal antibody, which is specifically reacting with a polypeptide of the invention in an immunoassay, or a specific binding fragment of said antibody, is also a part of the invention. The antibodies can be produced by methods known to a person skilled in the art. Polyclonal antibodies can be raised in a mammal, for example, by one or more injections of a polypeptide according to the present invention and, if desired, an adjuvant. The monoclonal antibodies according to the present invention may, for example, be produced by the hybridoma method first described by Kohler and Milstein (Kohler and Milstein, 1975), or may be produced by recombinant DNA methods such as described in U.S. Pat. No. 4,816,567. The monoclonal antibodies may also be isolated from phage libraries generated using the techniques described by McCafferty et al (McCafferty, 1990), for example. Methods for producing antibodies are described in the literature, e.g. in U.S. Pat. No. 6,136,958.
A sample of a potentially infected organ or body fluid from an infected individual may be contacted with such an antibody recognizing a polypeptide of the invention. The demonstration of the reaction by means of methods well known in the art between the sample and the antibody will be indicative of an ongoing infection. It is of course also a possibility to demonstrate the presence of anti-mycobacterial antibodies in serum or other body fluids by contacting a serum sample from a subject with at least one of the polypeptide fragments of the invention and using well-known methods for visualizing the reaction between the antibody and antigen.
In diagnostics, an antibody, a nucleic acid fragment and/or a polypeptide of the invention can be used either alone, or as a constituent in a composition. Such compositions are known in the art, and comprise compositions in which the antibody, the nucleic acid fragment or the polypeptide of the invention is coupled, preferably covalently, to at least one other molecule, e.g. a label (e.g. radioactive or fluorescent) or a carrier molecule.
It will be understood that the following examples are illustrative of the present invention and are not a limitation thereof. A number of variations on the techniques, reagents, and conditions described in the following examples will be readily apparent to one of skill in the art.
A number of M. tuberculosis genes are induced under low oxygen conditions. The up-regulation of the genes listed in table 2 has been determined at either the mRNA (Sherman, 2001) or protein (Boon, 2001, Rosenkrands, 2002) level. The coding region of these selected antigens is amplified by PCR using the primer sets listed in Table 3.
PCR reactions were carried out using Platinum Tag DNA Polymerase (GIBCO BRL) in a 50 μl reaction volume containing 60 mM Tris-SO4 (pH 8.9), 18 mM Ammonium Sulfate, 0.2 mM of each of the four nucleotides, 0.2 μM of each primer and 10 ng of M. tuberculosis H37Rv chromosomal DNA. The reaction mixtures were initially heated to 95° C. for 5 min., followed by 35 cycles of: 95° C. for 45 sec, 60° C. for 45 sec and 72° C. for 2 min. The amplification products were precipitated by PEG/MgCl2, and dissolved in 50 μL TE buffer.
DNA fragments were cloned and expressed in Gateway Cloning system (Life Technology). First, to create Entry Clones, 5 μL of DNA fragment was mixed with 1 μL of pDONR201, 2 μL of BP CLONASE enzyme mix and 2 μL of BP reaction buffer. The recombination reactions were carried out at 25° C. for 60 min. After Proteinase K treatment at 37° C. for 10 min., 5 μL of each sample was used to transform E. coli DH5α competent cells. Transformants were selected on LB plates containing 50 μg/mL kanamycin. One bacterial clone from each transformation was grown in 3 mL LB medium containing 50 μg/mL kanamycin and plasmid DNA was isolated (Qiagen).
Second, to create expression clones, 2 μL of each entry clone DNA was mixed with μL of His-tagged expression vector (pDest17), 2 μL LR reaction buffer, 2 μL LR CLONASE enzyme mix and 3 μL TE. After recombination at 25° C. for 60 min. and Proteinase K treatment at 37° C. for 10 min., 5 μL of each sample was used to transform E. coli BL21-SI competent cells. Transformants were selected on LBON (LB without NaCl) plates containing 100 μg/mL ampicillin. The resulting E. coli clones express recombinant proteins carrying a 6-histine tag at the N-terminal. All clones were confirmed by DNA sequencing.
Recombinant proteins were purified from transformed E. coli BL21-SI cells cultured in 900 mL LBON medium containing 100 μg/mL at 30° C. until OD600=0.4-0.6. At this point 100 mL 3 M NaCl was added and 3 hours later bacteria were harvested by centrifugation. Bacteria pellets were resuspended in 20 mL bacterial protein extraction reagent (Pierce) incubated for 10 min. at room temperature and pelleted by centrifugation. Bacteria were lysed and their DNA digested by treating with lysozyme (0.1 mg/mL) and DNase I (2.5 μg/mL) at room temperature for 30 minutes, with gentle agitation. The recombinant protein forms inclusion bodies and can be pelleted by centrifugation at 27.000×g for 15 min. Protein pellets were solubilized by adding 20 ml of sonication buffer (8 M urea, 50 mM Na2HPO4, 100 mM Tris-HCl, pH 8.0) and sonicating 5×30 sec pulses interrupted by a 30 sec pause. After another centrifugation at 27.000×g for 15 min., supernatants were applied to 10 mL TALON columns (Clontech). The columns were washed with 50 mL sonication buffer. Bound proteins were eluted by lowering pH (8 M urea, 50 mM Na2HPO4, 100 mM Tris-HCl, pH 4.5). 5 mL fractions were collected and analyzed by SDS-PAGE. Fractions containing recombinant protein were pooled. Further purification was achieved by anion- or cation-exchange chromatography on Hitrap columns (Pharmacia). Bound protein was eluted using a NaCl gradient from 0-500 mM in 3 M urea, 10 mM Tris-HCl, pH 8.0. All fractions were collected and analyzed on SDS-PAGE using Coomassie staining. Fractions containing recombinant protein were pooled. Final protein concentrations were determined by micro BCA (Pierce).
A prophylactic vaccine given prior to infection should induce an immune response sufficiently strong to prevent or dampen the initial proliferation of the bacteria in the acute phase and thereby reduce the ensuing disease. In the murine prophylactic vaccine model outlined in
To define the optimal components for a therapeutic vaccine, a murine reactivation model of latent TB has been established (van Pinxteren, 2000) (
The effect of the antigens in a prophylactic or a therapeutic vaccine.
BCG, ESAT6, and Rv2031c, one of the most prominent proteins induced under low oxygen conditions (Rosenkrands, 2002), were analyzed for their prophylactic and therapeutic vaccine potential. Naïve or latently infected C57Bl mice were immunized with one s.c. injection of 2.5×105 BCG, or 3 s.c. immunizations of 10 μg of either recombinant ESAT6 or recombinant Rv2031c in a DDA/MPL adjuvant. The vaccinations were done in groups of 5 mice and protective capacity of the vaccines was evaluated as described above.
There is a high variability in bacterial load intrinsic to the reactivation model in the latent and reactivation phase. The analysis of Rv2031c as a therapeutic vaccine was therefore repeated in groups of eight mice. As in the previous experiments the mice were given 3 s.c. immunizations of 10 μg rRv2031c in DDA/MPL. The induced immune responses were analyzed one week post immunization. The mice were partially bled and the PBMC from the blood purified and analyzed for Rv2031c- and ESAT6 specific recall responses. Using ELIspot technique, the frequency of Rv2031c-specific and ESAT6-specific IFN-γ-producing cells were determined in both the rRv2031c immunized and the unimmunized group (
To analyze the epitope recognition pattern of Rv2031c, fourteen overlapping peptides (each 20 amino acids long) covering the whole Rv2031c protein were synthesized. Initially the peptides were analyzed in 4 pools of 3-4 peptides. PBMCs from rRv2031c immunized latently-infected mice were incubated with the peptide pools (5 μg/ml per peptide) for 72 h. The specific peptide-induced IFN-γ production was quantitated in the supernatant in a standard sandwich ELISA using paired anti-murine IFN-γ antibodies (PharMingen) and recombinant IFN-γ (PharMingen) as standard. Both peptide pool 1-4 and 8-10 stimulated a significant IFN-γ response (
The therapeutic effect of the rRv2031c immunizations was analyzed 7 weeks after the last immunization.
Rv0569 is also a low oxygen induced antigen described in WO0179274 and illustrates very well the potential as a therapeutic vaccine.
We have established a murine reactivation model of latent TB [van Pinxteren et al, 2000, 30:3689-98], which is a variant of the so-called Cornell model. An aerosol infection is allowed to be established and at the peak of infection 6 weeks after, the mice receive an 8-week course of anti-mycobacterial drug treatment of isoniazid and rifabutin given in the drinking water. This reduces the bacterial load in spleen and lung to a low level. This latent phase of low chronic infection is stable for 9-10 weeks after which a slow spontaneous reactivation can be detected. This model is used to analyze the protective effect of a post exposure vaccine on reactivation.
Rv0569, which is highly up regulated under low oxygen growth conditions [Rosenkrands et al, 2002, 184(13): 3485-91], was analyzed for its ability to protect against reactivation given as a therapeutic vaccine in the latent phase of TB infection. Latent infected C57Bl mice were vaccinated with 3 s.c. injections of 3 μg recombinant Rv0569 and for comparison with 3 s.c. injections of 3 μg recombinant ESAT6 or one s.c. injection of BCG. The effect of the vaccine is evaluated 7 weeks after the last immunization. The induced immune responses were analyzed for Rv0569 or ESAT6 specific responses in an in vitro recall assay. Isolated splenocytes were incubated with 1 μg/ml of Rv0569 or 1 μg/ml of ESAT6 for 72 h. The produced IFNγ in the culture supernatant was quantitated in a standard sandwich ELISA.
The Rv0569 induced protection against reactivation was determined by enumeration of bacteria in spleen and lung 7 weeks after the last immunization.
All documents listed above, and the sequence listing, are incorporated by reference herein. A variety of modifications and variations on the processes, conditions, reagents and compositions described herein will be readily apparent to one of skill in the art given the teachings of the present invention. Such modifications and variations are within the scope of the invention as set forth in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| PA 2002 01098 | Jul 2002 | DK | national |
This application is a division of U.S. patent application Ser. No. 12/785,053, filed May 21, 2010, which is a continuation of U.S. patent application Ser. No. 10/617,038, filed Jul. 11, 2003, now abandoned, which claims the benefit of the priority of U.S. Provisional Patent Application No. 60/401,725, filed Aug. 7, 2002, now expired, and the priority of Danish Patent Patent Application No. PA 2002 01098, filed Jul. 13, 2002, which applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60401725 | Aug 2002 | US |
| Number | Date | Country | |
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| Parent | 12785053 | May 2010 | US |
| Child | 13369411 | US |
| Number | Date | Country | |
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| Parent | 10617038 | Jul 2003 | US |
| Child | 12785053 | US |
