Patent Application
20170165346
The content of the following submission on ASCII text file is incorporated herein by reference in its entirety: a computer readable form (CRF) of the Sequence Listing (file name: 303822001.208SeqList.txt, date recorded: Feb. 16, 2017, size: 15,753 KB).
This invention relates to compositions comprising combinations of biological molecules from Neisseria bacteria, particularly N. meningitidis and N. gonorrhoeae.
Neisseria meningitidis and Neisseria gonorrhoeae are non-motile. Gram negative diplococci that are pathogenic in humans.
Based on the organism's capsular polysaccharide, 12 serogroups of N. meningitidis have been identified. Group A is the pathogen most often implicated in epidemic disease in sub-Saharan Africa. Serogroups Band Care responsible thr the vast majority of cases in the United States and in most developed countries. Serogroups W135 and Y are responsible for the rest of the cases in the United States and developed countries.
The meningococcal vaccine currently in use is a tetravalent polysaccharide vaccine composed of serogroups A, C, Y and W135. Meningococcus B remains a problem, however, The polysaccharide approach cannot be used because the menB capsular polysaccharide is a polymer of α(2-8)-linked N-acetyl neuraminic acid that is also present in mammalian tissue. One approach to a menB vaccine uses mixtures of outer membrane proteins (OMPs). To overcome the antigenic variability, multivalent vaccines containing up to nine different porins have been constructed [eg. Poolman J T (1992) Development of a meningococcal vaccine. Infect. Agents Dis. 4:13-28). Additional proteins to be used in outer membrane vaccines have been the opa and opc proteins, but none of these approaches have been able to overcome the antigenic variability [eg. Ala'Aldeen & Borriello (1996) The meningococcal transferrin-binding proteins 1 and 2 are both surface exposed and generate bactericidal antibodies capable of killing homologous and heterologous strains. Vaccine 14(1):49-53].
Given the propensity for meningococcal disease during non-epidemic periods to be caused by multiple strains or strain variants [Russel et at. (1998) Abstracts of 11th International pathogenic Neisseria conference, page 281] together with frequent temporal shifts in the predominant strains in a community, it seems that a universal meningococcal B vaccine will require more than one antigenic species.
Neisserial protein and nucleotide sequences are disclosed in the following documents:
For ease of reference, the sequences disclosed in these documents are referred to in the present application accordion to the following table:
Science
The present invention provides compositions comprising a first biological molecule from a Neisseria bacterium and a second biological molecule from a Neisseria bacterium. The term “biological molecule” includes proteins and nucleic acids.
The compositions may also comprise further biological molecules, preferably also from Neisseria, that is to say the compositions may comprise two or more biological molecules (eg. 3, 4, 5, 6, 7, 8 etc.), at least two of which are from a Neisseria bacterium (eg. 3, 4, 5, 6, 7, 8 etc.). Such compositions include those comprising (i) two or more different Neisserial proteins, (ii) two or more different Neisserial nucleic acids, or (iii) mixtures of one or more Neisserial protein and one or more Neisserial nucleic acid.
In one preferred embodiment, the first and second biological molecules are from different Neisseria species (eg. one is from N. meningitidis and one is from N. gonorrhoeae), but they may be from the same species. The biological molecules in the compositions may be from different serogroups or strains of the same species.
The first biological molecule is preferably selected from the group consisting of SEQ IDs 1-8376. More preferably it is selected from the group consisting of SEQ IDs 1-4002 and/or SEQ IDs 4057-8376. It is preferably a purified or isolated biological molecule.
The second biological molecule is preferably selected from the group consisting of SEQ IDs 1-8376. More preferably, it is selected from the group consisting of SEQ IDs 1-4002 and/or SEQ IDs 4057-8376. It is preferably a purified or isolated biological molecule.
One or both of the first and second biological molecules may be a Neisserial biological molecule which is not specifically disclosed herein, and which may not have been identified, discovered, made available to the public or purified before this patent application was filed.
In particular, the invention provides a composition comprising one or more of the following pairs of first and second biological molecules (listed by SEQ ID):
Thus the invention includes each of the 35074500 possible pairs of SEQ IDs 1-8376 (1&2, 1&3, 1&4, 1&5 . . . 1&8375, 1&8376, 2&3, 2&4, 2&5 . . . 2&8375, 2&8376, 3&4 . . . 1000&1001, 1000&1002 . . . 1000&8376 . . . 8374&8375, 8374&18376, 8375&8376) although, for reasons of space these are not listed in full here.
Details as to how the molecules which make up the SEQ IDs 1-4056 can be produced and used can be found from the relevant international applications and these details need not he repeated here. Similar principles apply to SEQ IDs 4057-8376.
SEQ IDs 1-8376 in the compositions of the invention may be supplemented or substituted with molecules comprising sequences homologous (ie. haying sequence identity) to SEQ IDs 1-8376. Depending on the particular sequence the degree of identity is preferably greater than 50% (eg. 65%, 80%, 90%, or more), and include mutants and allelic variants. Sequence identity between the proteins is preferably determined by the Smith-Waterman homology search algorithm as implemented in the MPSRCH program (Oxford Molecular), using an affine gap search with parameters gap open penalty=12 and gap extension penalty=1.
SEQ IDs 1-8376 in the compositions of the invention may be supplemented or substituted with molecules comprising fragments of SEQ IDs 1-8376. Such fragments should comprise at least n consecutive monomers from the molecules and depending on the particular sequence, n is either (i) 7 or more for protein molecules (eg. 8, 10, 12, 14, 16, 18, 20 or more), preferably such that the fragment comprises an epitope from the sequence, or (ii) 10 or more for nucleic acid molecules 14, 15, 18, 20, 25, 30, 35, 40 or more).
Where the composition includes a protein that exists in different nascent and mature forms, the mature form of the protein is preferably used. For example, the mature form of the NspA protein (SEQ IDs 4008-4033: WO96/29412:
In the case of protein molecules, SEQ IDs 1-8376 in the compositions of the invention may be supplemented or substituted with an antibody that binds to the protein. This antibody may be monoclonal or polyclonai.
In the case of nucleic acid molecules, SEQ IDs 1-8376 in the compositions of the invention may be supplemented or substituted with nucleic acid which can hybridise to the Neisserial nucleic acid, preferably under “high stringency” conditions (eg. 65° C. in a 0.1×SSC, 0.5% SDS solution).
It will be appreciated that any nucleic acid in the compositions can take various forms (eg. single stranded, double stranded, vectors, probes etc.). In addition, the term “nucleic acid” includes DNA and RNA, and also their analogues, such as those containing modified backbones, and also peptide nucleic acids (PNA) etc.
In certain embodiments, the composition comprises molecules from different Neisseria species, such as one or more N. meningitidis molecule and one or more N. gonorrhoeae molecule. In some embodiments, the composition may comprise molecules from different serogroups and/or strains of the same species, such as strains A and B of N. meningitidis. Further embodiments comprise mixtures of one or more N. meningitidis molecules from different strains and also one or more N. gonorrhoeae molecules.
Many proteins are relatively conserved between different species, serogroups and strains of N. meningitidis and N. gonorrhoeae (eg. SEQ IDs 52, 54, 58). PCT/IB00/00642 includes a more detailed experimental analysis of conserved regions in these proteins. To ensure maximum cross-strain recognition and reactivity, regions of proteins that are conserved between different Neisserial species, serogroups and strains can be used in the compositions of the present invention. The invention therefore provides proteins which comprise stretches of amino acid sequence that are shared across the majority of Neisseria, particularly N. meningitidis and N. gonorrhoeae. Preferably, therefore, the composition comprises a protein comprising a fragment of a Neisserial protein (preferably a protein from SEQ IDs 1-8376, or more preferably SEQ IDs 1-4002), wherein said fragment consists of n consecutive conserved amino acids. Depending on the particular protein, n is 7 or more (eg. 8, 10, 12, 14, 16, 18, 20 or more). The fragment preferably comprises an antigenic or immunogenic region of the Neisserial protein. A “conserved” amino acid is one that is present in a particular Neisserial protein in at least x % of Neisseria (or, preferably, in at least x % of combined N. meningitidis and N. gonorrhoeae strains). The value of x may be 50% or more eg. 66%, 75%, 80%, 90%, 95% or even 100% (ie. the amino acid is found in the protein in question in all Neisseria). In order to determine whether an amino acid is “conserved” in a particular Neisserial protein, it is necessary to compare that amino acid residue in the sequences of the protein in question from a plurality of different Neisseria (a “reference population”). Suitable definitions of “reference populations” can he found in PCT/IB00/00642. Amino acid sequences of different Neissieriae can easily be compared using computers. This will typically involve the alignment of a number of sequences using an algorithm such as CLUSTAL [Thompson et al. (1994) Nucleic Acids Res 22:4673-4680: Trends Biochem Sci (1998) 23:403-405] or, preferably, PILEUP [part of the GCG Wisconsin package, preferably version 9.0]. Conserved amino acids are readily apparent in a multiple sequence alignment— at the amino acid position in question a majority of the aligned sequences will contain a particular amino acid. Conserved amino acids can be made more visually apparent by using a program such as BOXSHADE [available, for instance, at the NIH on-line], PRETTYBOX [GCG Wis., version 10] or JALVIEW [available on-line at EBI].
Specific compositions according to the invention therefore include those comprising:
The invention also provides the compositions of the invention for use as medicaments (eg. as immunogenic compositions or vaccines) or as diagnostic reagents. It also provides the use of the compositions in the manufacture of: (i) a medicament for treating or preventing infection due to Neisserial bacteria: (ii) a diagnostic reagent for detecting the presence of Neisserial bacteria or of antibodies raised against Neisserial bacteria; and/or (iii) a reagent which can raise antibodies against Neisserial bacteria.
The invention also provides a method of treating a patient, comprising administering to the patient a therapeutically effective amount of a composition according to the invention.
The invention further provides a process for producing a composition according to the invention, comprising the step of bringing one or more of SEQ IDs 1-8376 into combination with one or more other of SEQ IDs 1-8376.
ORFs 6, 7, 13, 65-1, 72, 73-1, 105-1, 137-1, 143-1 and 147-1 disclosed in WO99/24578 were expressed in E. coli and purified, as set out in the following table:
The protocols used to express these ten ORFs were essentially the same as those described in WO99/124578, using pGEX and pET vectors. Examples of the PCR primers used to amplify the ORFs are in the following table:
SDS-PAGE results for the ten expressed ORFs are shown in
The ORF7-His fusion was used to immunise mice. The sera were used in an ELISA assay, essentially as described in WO99/24578, and gave positive results.
Each of these ORFs can be combined with one or more of SEQ IDs 1-8376.
ORF9 disclosed in WO99/24578 was cloned in the pET vector and expressed in E. coli. The purified ORF-His fusion protein was analysed by SDS-PAGE, as shown in
The results confirm that ORF9 is a surface-exposed protein, ORF9 is suitable for combining with one or more other of SEQ IDs -8376.
Further expression and purification experiments were carried out in E. coli for ORFs 2-1, 5-1, 22-1 and 132-1 disclosed in WO99/74578, as set out in the following table:
The protocols used to express these four ORFs were essentially the same as those described in WO99/24578, using pGEX and pET vectors. Examples of the PCR primers used to amplify the ORFs are in the following table:
SDS-PAGE results for the four expressed ORFS are shown in
Each of these ORFs can be combined with one or more of SEQ IDs 1-8376.
ORF4 is disclosed in WO99/24578 as containing a lipopeptide signal sequence (LPSS). The full length ORF was amplified using the following PCR primers:
The amplified DNA fragment was cloned into the vector pET21b+ for expression as a C-terminus His-tagged fusion. A log phase culture of E. coli containing pET21b+orf4-LPSS was induced with 1.0 mM IPTG for 3 h at 30° C. collected by centrifugation for 10 min at 8000g, and resuspended in PBS. The suspension was sonicated on ice and Triton X-114 added to a final concentration of 0.6% (w/v). The material was incubated on ice for 20 minutes then warmed to 37° C. until phase separation occurred (indicated by a high degree of cloudiness). After centrifugation for 10 min at 10.000 g at 20° C. the upper aqueous phase was discarded, and the lower detergent phase collected without disrupting the bacterial pellet. To the detergent phase was added 13 volumes of 20 mM Histidine, 2 mM EDTA, 30 mM NaCl (pH 5.8). This was centrifuged for 10 min at 4° C. and the supernatant combined batchwise at 4° C. for 30 min. with Q Sepharose Fast Flow resin (Pharmacia). The mixture was centrifuged, the supernatant retained and the resin washed with 20 mM Histidine, 2 mM EDTA, 30 mM NaCl (pH 5.8). Triton N-100 0.3% (w/v) and eluted with 1M NaCl in the same buffer. The majority of Orf4 lipoprotein was found in the supernatant obtained after binding. Final purification was accomplished by chromatography on Hi-Trap™ Q (Pharmacia). The binding-supernatant was adjusted to pH 7.0 by the addition of 0.1M HCl and applied to a Hi-Trap™ Q column equilibrated with 50mM Tris-HCl (pH 7.0), 2 mM EDTA, 0.3% Triton X-100, 10 mM NaCl. The column was washed with 5.0 ml of the equilibration buffer and a NaCl gradient from 10 mM to 1M was applied. Two electrophoretically distinct forms of the protein eluted. One in the wash and the other in the NaCl gradient between 150 mM and 300 mM NaCl. The protein obtained in the wash was used for immunization of mice. This form of the protein probably represents the fully processed. lipidated molecule.
The 31 kDa purified lipoprotein can be seen in
Computer analysis of ORFs 2, 5, 6a,7, 9, 13a, 15, 22, 23, 27, 28, 32, 65, 72, 73, 76, 79, 89, 105, 106-1, 132, 137, 138, 143 and 147 (as disclosed in WO99/24578 was performed.
Each of these ORFs can be combined with one or more other of SEQ IDs 1-8376.
A mixture of proteins 919 (WO99/57280), 225 (WO99/57280), ORF4 (WO99/24578, example 26) and ORF40 (WO99/36544, example 1) was produced and assessed by ELISA and FACS. The ELISA titres against 13 test strains were as follows:
The FACS results are shown in
A mixture of proteins ORF4-L (the lipidated protein—see example 4 above). ORF37 (WO99/24578, example 1). ORF40 (WO99/36544,example 1), 502 (WO99/57280, pages 687-690) and 8 (WO99/57280, pages 165-167) was produced. The ELISA titres against 13 test strains were as follows:
The FACS results are shown in
Proteins ORF1 (e.g. example 77 of WO99/24578: see also WO99/55873), ‘287’ (e.g,
This mixture was also combined with a MenC polysaccharide conjugate antigen [e.g. Costantino et al. (1992) Vaccine 10:691-698]. OMVs were used as controls.
The mixture was used in a bactericidal assay against the homologous strain and also heterologous MenB strains. Titres were as follows:
Proteins 287, 919 and 953 are disclosed in WO99/57280. These proteins from N. meningitidis scrogroup B strain 2996 were expressed and tested in a bactericidal assay against strain 2996, alone and in combinations. OMVs from 2996 were used as a positive control.
It is evident that the antigen mixtures are more effective than the antigens in isolation and in particular, that combinations of 919+953 give surprisingly good results.
The individual antigens from 2996 arid combinations were also tested against different serogroup A, B & C strains (i.e. heterologous challenge). Bactericidal titres were as follows:
It is apparent that the antigen mixtures are useful in conferring cross-strain activity.
In a second set of experiments. titres for the individual antigens were as follows:
The three proteins used in this example were expressed and used in the following forms:
Three immunisations were administered with Freund's adjuvants—the first included CFA, and the final two included IFA.
Further combinations of antigens were tested in CD1 mice:
Further combinations of antigens were tested in guinea pigs:
Evidently the combinations give excellent immunological results.
NspA protein is disclosed in WO96/29412, and is represented herein as SEQ IDs 4008-4033. The academie literature disclosure of this protein [Martin et al. (1997) J. Exp. Med 185 1173-1183] reported the protein to be highly conserved between Neisseria strains (99% cross-reactivity of anti-NspA antibodies with 250 meningococcal A, B & C strains) and also efficient protection against deadly challenge with live bacteria. There have also been reports that NspA adsorbed on alum elicits serum meningococcal bactericidal antibody responses in rabbits and monkeys [Martin et al. (1998) Abstracts of 11th International pathogenic Neisseria conference. page 198]. On the basis of these data, rNspA (recombinant NspA) is being developed as a vaccine for the prevention of meningococcal disease caused by all serogroups.
Despite sequence conservation, however, it has surprisingly been discovered that rNspA cell surface epitopes are detected on only 65% of the serogroup B strains tested below, and susceptibility to anti-NspA bactericidal activity is also less than that reported by Martin et al, These results contrast with Martin et al., and suggest that a rNspA-based meningococcal B vaccines will need to be supplemented with additional antigens in order to be effective.
The N. meningitidis strains tested in this example were isolated from patients residing in different countries over a period of more than 30 years (see table on page 72). These strains were selected to be representative of widely divergent ‘clonal’ groups, as defined by multilocus isoenzyme typing [Seiler et al. (1996) Mol. Microbiol. 19:841-856] and/or multilocus sequence typing [Maiden et al. (1998) PNAS USA 95:3140-45]. Strain M7, which is derived from strain NMB, contains a transposon insertion that blocks capsular polysaccharide biosynthesis [Stephens et al. (1991) Infect. Immun. 59:4097-4102]. but all the other strains are encapsulated.
Based on the nucleotide sequence in Martin et al. (1997), PCR primers were designed and the NspA gene from strain 8047 was amplified. The sequence, including, the promoter region, was cloned into pSK+ plasmid (rNspA). A plasmid pTre.NspA.1 encoding a protein in which a portion of the signal sequence has been replaced with a poly-histidine tag was also used. Both plasmids were expressed in E. coli strain BL21(DE3) and the proteins were purified. In E. coli, rNspA is secreted, rather than being, associated with the outer membrane. The protein was partially purified from the culture medium by precipitation with 55% w/v ammonium sulphate. and had an apparent MW of 18.6 kDa, confirmed by Western Blot.
The two forms of NspA (rNspA and denature His-tage NspA) were injected into 6-week old female CD-1 mice to raise antisera. The ability of these to bind to the surface of N. meningitidis strain B was determined using flow cytometric detection of indirect fluorescence assay [Granoff et al. (1998) J. Immunol. 160:5028-36]. The results for strains NMB and M7 (an acapsulated mutant of NMB) are shown in
These data suggest that antibodies prepared using His-tag NspA recognise epitopes that are present in denatured NspA, but not native NspA as found on the cell-surface in viva. In contrast, antibodies prepared against rNspA seem to recognise conformational NspA epitopes.
The flow cytometric assay was applied to the strains shown in the table on page 72.
The table on page 72 summarises the flow cytometry results. Although NspA is reported o be accessible at the surface of all intact N. meningitidis strains tested [Martin et al. (1997) J. Exp. Med 185 1173-1183; Plante et al. (1999) Infect. Inmun. 67:2855-61], only 11 of the 17 test strains (65%) reacted with the anti-rNspA sera. There was no apparent relationship between cell-surface expression in a given strain and classification (by serotype. subtype, or electrophoretic type), or with year or country of isolation.
In an attempt to explain the differences in reactivity with the anti-rNspA sera, the nspA genes from five of the six negative strains (BX232, NG3/88, NGP165, M136 & M986) and from three of the positive strains (8047, CU385 & NG6/88) were sequenced. The sequence for the sixth negative strain (MC58) was already available from the complete genome sequence.
The nspA sequences for all ten strains were highly conserved, varying at most by 5 nucleotides from the prototype sequence of Martin et al. The most variant protein had only 3 amino acid differences (see
As neither lack of the gene nor polymorphism explained the antiserum results, the amount of NspA protein in the outer membranes of five strains (8047, CU385 & NG6/88—all positive for anti-rNspA; M986 & M136—both negative) were tested. Bacterial cell pellets were extracted with lauryl sarcosinate, and the insoluble outer membrane fractions were analysed. An 18.6 kDa band was seen for all five strains, and this was cross-reactive with anti-His-tag-NspA by Western Blot. Thus strain differences in nspA expression also failed to explain the results.
The ability of anti-rNspA to bind to the bacterial cell surface could be influenced by the amount of polysaccharide capsule present. The quantity of capsular polysaccharide produced by the 17 test strains was therefore assessed by inhibition ELISA.
Extracts of capsular polysaccharide were prepared based on a method described by Corn et al. [J. Infect. Dis. (1993) 167:356-64]. Individual bacterial clones were grown to an OD620 0.5-0.7 in 7 mL of Mueller-Hinton broth. Bacteria were collected by centrifugation at 5000 g for 15 min, washed in 0.6 mL of 10 mM Hepes, pH 8.0, and then resuspended in 0.6 mL of the same buffer containing 10 mM EDTA and incubated at 37° C. for 1 hr. The cells were pelleted at 10,000 g for 1 minute and the relative amount of meningococcal B polysaccharide antigen released into the supernatant was determined by an inhibition ELISA, performed as described by Azmi et al. [Infect Immun. (1995) 63:1906-13]. The solid phase antigen in the ELISA was meningococcal B polysaccharide-ADH-biotin absorbed to avidin-coated inicrotiter plates [Granoff et al.]. The meningococcal B polysaccharide-reactive human paraprotein LIP [Azmi et al.] was used as the primary antibody (0.2 μg/ml ). In the absence of inhibitor, this concentration of antibody was sufficient to given an OD of ˜0.7 to 1.0 after 30 minutes incubation with substrate [Azmi et al.] The titre of polysaccharide released into the supernatant was measured by determining the dilution of supernatant that resulted in 50% inhibition of antibody binding. Controls in this assay included an EDTA extract prepared from the strain M7, which does not produce any capsular polysaccharide, and purified meningococal B polysaccharide. To ensure that all of the capsular polysaccharide was released by the EDTA treatment, the same inhibition ELISA was performed using the cell pellet resuspended in the same buffer and volume as the capsule extract. The observable inhibitory activity from the cell pellet was between 0 and 10% of the activity observed in the capsule extracts with the latter. higher percentage coming from cell pellets of strains that produce the largest amounts of capsule.
The results for each strain are shown in the table on page 72. On average, the six negative anti-rNspA strains produced three-fold more capsular polysaccharide than the eleven positive strains (respective reciprocal geometric mean dilutions of 676 vs. 224, p<0.05). This may explain the results obtained with the antiserum conceivably, the presence of larger amounts of capsule could interfere with the ability of the anti-rNspA antibody to bind to NspA epitopes which, in strains with lower amounts of capsule, are accessible.
The complement-dependent bactericidal activity of the anti-rNspA antisera were tested using an assay similar to that described by Mandrell et al, [J. Infect. Dis. (1995) 172:1279-89]. The complement source was human serum from a healthy adult with no detectable anti-capsular antibody to group B polysaccharide and no intrinsic bactericidal activity against the test strain. Serum bactericidal titres were defined as the serum dilution resulting in a 50% decrease in CFU/ml after 60 minutes incubation of bacteria in the reaction mixture, compared to the control CFU/ml at time zero.
Typically, bacteria incubated with a negative control antibody showed a 150-200% increase in CFU/ml during the 60 minutes of incubation. The positive control antibody [anti-capsular IgG2a MAb SEAM 12, Granoff et al.] showed complement-mediated bactericidal activity against all 17 strains. In contrast, the six strains that were negative for anti-rNspA antisera binding by flow assay were resistant, showing no bactericidal or bacteriostatic effects. Ten of the other eleven positive strains were either killed by complement and the antisera (SWZ107, J351, CU385, NG6/88, BZ198, 1144/76, NMB & 8047) or were inhibited (H355 & S3446); strain 1000, however, was not affected.
The ability of the anti-rNspA antisera to confer passive protection against meningococcal B bacteremia was tested in infant rats using a method adapted from Saukkonen [J. Infect. Dis. (1988 ) 158:209-212]. Briefly, 6-7 day old rats were randomly distributed to nursing mothers. Groups of 5-6 animals were challenged IP with 100 μl of approximately 5000 CFU of N. meningitidis group B bacteria. One strain negative for NspA surface epitopes (M986) and one positive strain (8047) were tested, each of which having been passaged three times in infant rats. Immediately before administration, the bacterial suspension was mixed with different dilutions of test or control antibody (positive control: anticapsular mAb; negative control: anti-E. coli). 18 hours after challenge, blood specimens were obtained from the heart. Aliquots were plated onto chocolate agar, and CFU/ml was determined after overnight incubation at 37° C. in 5% CO2.
The protective activities of the various co-administered antibodies were as follows:
ap > 0.5, compared to geometric mean CFU/ml of control rats
bp < 0.001, compared to geometric mean CFU/ml of control rats
As can be seen, a dose of 2 μg per rat of the positive anticapsular control was protective against both strains. A 1:5 or 1:25 dilution of anti-rNspA antiserum protected against hacteremia caused by strain 8047. Neither dilution was effective in preventing M986 bacteremia, however.
Despite the positive conclusions of Martin et al., therefore, NspA does not seem to be effective in preventing meningococcal B infection. Approximately one third of strains have decreased cell-surface expression of NspA epitopes when grown in vitro, are resistant to anti-NspA induced complement-mediated bacteriolysis, and are resistant to passive antiserum immunisation. These strains produce large amounts of capsular polysaccharide, and would thus be expected to have the greatest virulence. The ability of a vaccine containing only NspA to confer broad protective immunity against meningococcal B thus has to be doubted.
Compositions comprising NspA [SEQ IDs 4008-4033;
A model of the secondary structure of NspA is shown in
The grey shaded areas in the model indicate segments that are >40% identical and >70% similar to encoded amino acid sequences of opacity proteins (Opa) from N. meningitidis, N. gonorrhoeae, N. flavius, N. sicca, and H. influenzae identified in a BLAST search of the non-redundant GenBank CDS. The alternating sequences are predicted amphiphilic β-strands; vertical segments correspond to transmembrane segments; the top of the figure corresponds to surface exposed segments, labelled as loops 1 to 4.
According to Martin et al., the only significant homology between the deduced amino acid sequence of NspA and those of other proteins are weak homologies with the Neisseria opacity protein (Opa) family in two small segments (˜20 amino acids) near the C-terminal end of the protein . However, separate comparisons of the N- and C-termini of NspA with GenBank reveals a high degree of homology (>40% identity and >70% similarity) between NspA and Opa proteins from N. meningitidis, N. gonarrhoeae, N. flavius, N. sicca, and H. influenzae. The Opa proteins are thought to be integral membrane proteins that have eight transmembrane segments and a β-barrel topology in the membrane similar to that of porin [Merker et al. (1997) Mol. Microbial. 23:281-293]. The presence of NspA in detergent-insoluble membrane preparations indicate that NspA is located in the outer membrane, which would be consistent with the Opa-like membrane topology shown in the model. In addition, the segments of NspA that are most homologous to those of the Opa proteins are the putative transmembrane segments indicated in the shaded areas of
The opacity proteins of Neisseria can, under certain circumstances, elicit protective antibody. However, problems with limited antibody accessibility of the opacity proteins in encapsulated bacteria, variability of amino acid sequences in exposed loop segments, and phase variation of protein expression during clinical infection, have limited the ability of Opa to elicit protective antibody consistently [Malorny et al. (1998) J. Infect. Dis. 172:1279-89]. In contrast, there appears to be little or no sequence variation in the surface exposed loops of NspA in
Accordingly, the invention provides the fragments of NspA that are exposed on the cell-surface in
These NspA fragments, proteins comprising the fragments, and nucleic acid, may be used in the compositions of the invention, in particular as substitutes for full-length NspA. In a further aspect, these fragments, proteins and nucleic acids may be used as products in isolation, that is to say they need not exclusively be used in combination with other biological molecules.
It will be appreciated that the invention has been described by means of example only, and that modifications may be made whilst remaining within the spirit and scope of the invention.
Neisseria meningitidis B bacteria in relation to susceptibility to bacteriolysis and capsular production.
a Denotes strains that have been characterized further by multilocus sequence typing [Maiden, 1998].
b Denotes strains obtained from the Frasch collection, US FDA. 8047 was obtained from W. Zollinger, Walter Reed Army Institute of Research, Washington, D.C. MC58 is the strain selected by TIGR for genomic sequencing. J351 was obtained from M. Sarvas, National Public Health Institute, Helsinki, Finland. The remaining strains are from the collection described by Seiler et al. [Seiler, 1996]. ET data are from Caugnant et al. [j. Infect. Dis. (1990) 162: 867-874], and Seiler et al.
c By indirect fluorescence flow cytometry with anti-rNspA antisera.
d Dilution of anti-rNspA antisera that when incubated for 60 min. with bacterial cells and 20% human complement yielded ≧50% decrease in CFU/ml, compared to that at time 0. “Static” refers to strains that were inhibited but not killed in the assay (≧50% but <100% survival at 60 mins).
e Titre defined as dilution of capsule extract giving 50% inhibition of antibody binding to meningococcal B polysaccharide antigen in an EL1SA.
| Number | Date | Country | Kind |
|---|---|---|---|
| 9911692.3 | May 1999 | GB | national |
| 9919705.5 | Aug 1999 | GB | national |
| 0005730.7 | Mar 2000 | GB | national |
All documents cited herein are incorporated by reference in their entirety. This application is a Continuation of U.S. patent application Ser. No. 15/015,004, filed Feb. 3, 2016, which is a Continuation of U.S. patent application Ser. No. 14/284,326, filed May 21, 2014, (now Abandoned), which is a Continuation of U.S. patent application Ser. No. 13/921,087, filed Jun. 18, 2013, (now Abandoned), which is a Continuation of U.S. patent application Ser. No. 12/979,239, filed Dec. 27, 2010, (now Abandoned), which is a Continuation of U.S. patent application Ser. No. 10/982,703, filed Nov. 5, 2004, (now U.S. Pat. No. 7,862,827), which is a Continuation of U.S. patent application Ser. No. 09/979,263, which claims an international filing date of May 19, 2000, (now Abandoned), which is the National Stage of international patent application Ser. No. of PCT/IB2000/1000828, filed May 19, 2000, which claims the benefit of United Kingdom Patent Application No. 9911692.3, filed May 19, 1999, United Kingdom Patent Application No. 9919705.5, filed Aug. 19, 1999, and United Kingdom Patent Application No. 0005730.7, filed Mar. 9, 2000, each of which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15015004 | Feb 2016 | US |
| Child | 15438584 | US | |
| Parent | 14284326 | May 2014 | US |
| Child | 15015004 | US | |
| Parent | 13921087 | Jun 2013 | US |
| Child | 14284326 | US | |
| Parent | 12979239 | Dec 2010 | US |
| Child | 13921087 | US | |
| Parent | 10982703 | Nov 2004 | US |
| Child | 12979239 | US | |
| Parent | 09979263 | Aug 2002 | US |
| Child | 10982703 | US |
