首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Chaperonin CCT containing t-complex polypeptide 1 is a cytosolic molecular chaperone that assists in the folding of actin, tubulin, and other proteins and is a member of the 60-kDa heat shock protein (Hsp60) family. We examined antibody titers against human CCT and other Hsp60 family members in the sera of patients with rheumatic autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematodes, Sj?gren syndrome, and mixed connective tissue disease. Autoantibody titers against not only human mitochondrial Hsp60 but also CCT were significantly higher in the sera of patients with rheumatic autoimmune diseases than in healthy control sera. Although immunoglobulin G (IgG) titers against Escherichia coli GroEL were high in all the groups of sera tested, no significant differences in anti-GroEL responses were detected between patients and healthy controls. IgG titers against mycobacterial Hsp65 showed a similar pattern to titers of autoantibodies recognizing GroEL. Immunoabsorption experiments demonstrated that most of the autoantibodies recognizing CCT were cross-reactive with mitochondrial Hsp60, E coli GroEL, and mycobacterial Hsp65. Although most of the anti-Hsp60 IgG recognized CCT, anti-GroEL (or antimycobacterial Hsp65) IgG contained antibodies specific for GroEL (or mycobacterial Hsp65) in addition to antibodies cross-reactive with CCT and Hsp60. Results from immunoblot analyses, together with weak (15% to 20%) amino acid sequence identities between CCT and the other Hsp60 family members, suggested that CCT-reactive autoantibodies recognize conformational epitopes that are conserved among CCT and other Hsp60 family members.  相似文献   

2.
Abstract Porphyromonas gingivalis is associated with human periodontal disease. We cloned and sequenced the gene for heat shock protein 60 (GroEL, HSP60) from P. gingivalis FDC381. The identified clone carried a 2.6 kb DNA fragment which contained two open reading frames (ORFs) encoding a 9.6- and a 58.4-kDa protein. The translated amino acid sequence of these ORFs showed a high degree of homology with known sequences for GroES and GroEL from several bacterial species and humans. Escherichia coli carrying this clone expressed a 65-kDa protein which was recognized by anti- Mycobacterium leprae HSP60 monoclonal antibody. We purified the 65-kDa protein by DEAE-sepharose chromatography and hydroxyapatite chromatography. This protein was immunogenic and was recognized by sera from a number of patients with periodontal disease. This immunological reactivity and the existence of molecular mimicry between the P. gingivalis GroEL and other HSP homologs may indicate an important role for this molecule in periodontal lesion.  相似文献   

3.
应用免疫组化方法证实560%的成年人牙周炎(AP)患者的牙龈组织的成纤维细胞中存在牙龈紫质单胞菌内毒素(Pg-LPS),正常的牙龈组织样本无一例阳性。以免疫胶金技术发现Pg-LPS在5min内即能侵入体外培养的小鼠成纤维细胞,至60min时可在细胞核内检出Pg-LPS。Pg-LPS检测阳性的小鼠成纤维细胞和AP患者牙龈组织的成纤维细胞的可出现相似的内质网扩张、膜旁核糖体颗粒脱落、线粒体的外膜或嵴消失等超微结构病变。实验结果表明,Pg-LPS是AP的主要致病因子之一。  相似文献   

4.
乳房链球菌Streptococcus uberis的GapC蛋白是一种位于该菌表面的具有甘油醛-3-磷酸脱氢酶活性的蛋白,其参与细胞活动,表现出多种生物学活性,此外还具有良好的抗原性。文中旨在对乳房链球菌GapC蛋白可能的B细胞抗原表位进行预测,分析和验证候选表位肽的免疫原性。利用S. uberis分离株RF5-1克隆gapC基因,构建重组表达质粒pET-28a-GapC,诱导表达GapC重组蛋白,并以纯化蛋白免疫家兔,获得抗GapC多抗。利用生物信息学软件预测并分析GapCB细胞抗原表位的三维结构和空间位置及对GapC蛋白及表位的同源性比较。结果表明,表达纯化了44kDa的GapC蛋白具有良好的反应性。利用表位预测软件筛选并合成针对S.uberisGapC蛋白的6个线性和3个构象优势B细胞表位多肽,三维结构的分析显示,筛选的多肽具有良好的抗原表位形成条件。以纯化的S.uberis GapC蛋白免疫家兔制备多抗,通过间接ELISA对抗原表位进行鉴定。ELISA检测结果显示,9条抗原表位肽均可不同程度地与抗GapC多抗反应,其中表位266AANDSYGYTEDPIVSSD282与多抗反应...  相似文献   

5.
Immunoaffinity purification of hsp90 from chick oviduct cytosol reveals two major proteins, hsp70 and a 60-kDa protein (p60), copurifying with hsp90. A similar result is obtained when hsp90 is immunoaffinity purified from chick liver and brain cytosols, avian fibroblasts, and rabbit reticulocyte lysate. This p60 is the same protein previously identified in certain assembly complexes of chick progesterone receptor generated in a cell-free reconstitution system. Tryptic and cyanogen bromide peptide fragments were generated from gel-purified p60, and partial N-terminal sequences were determined from eight peptides. The sequences show a striking similarity to the sequence of a 63-kDa human protein (IEF SSP 3521) whose abundance is increased in MRC-5 fibroblasts following simian virus 40 transformation. A monoclonal antibody was prepared against avian p60; Western immunoblot analysis showed that p60 was present in each of eight chick tissues examined and in each of the human, rat, rabbit, and Xenopus tissues tested. Immunoaffinity purifications from both chick oviduct cytosol and rabbit reticulocyte lysate using anti-p60 and anti-hsp70 monoclonal antibodies confirm that there is a relatively abundant complex in these extracts containing hsp90, hsp70, and p60. This complex appears to comprise an important functional unit in the assembly of progesterone receptor complexes. However, judging from the abundance and widespread occurrence of this multiprotein complex, hsp90, hsp70, and p60 probably function interactively in other systems as well.  相似文献   

6.
The immune response to mycobacterial pathogens comprises a significant percentage of T cells with specificity for a 65-kDa heat shock protein (hsp) which is highly conserved in bacteria and man. PBMC were activated in vitro with killed Mycobacterium tuberculosis and afterward tested for CTL activity on autologous target cells primed with 1) killed M. tuberculosis, 2) intact recombinant 65-kDa hsp of Mycobacterium bovis/M. tuberculosis; or 3) tryptic fragments of the recombinant 65-kDa hsp. Strong CTL activity was observed on targets primed with killed M. tuberculosis or with tryptic fragments of the 65-kDa hsp, but not on those primed with the intact 65-kDa hsp. M. tuberculosis activated T cells from 2/13 donors tested exerted killer activity against unprimed targets. To assess whether T cell responses were directed against self-epitopes shared by the mycobacterial and human 65-kDa hsp, four peptides of at least 10 amino acids length were synthesized corresponding to fully or almost identical regions of these molecules. Peripheral blood T cells from 8/9 individuals tested, after activation with killed M. tuberculosis, expressed strong CTL activity toward autologous targets primed with one or more of these synthetic peptides. By using HLA-DR transfected murine L cells we found that the epitopes were recognized in the context of histocompatible HLA-DR (class II) molecules. We conclude that the demonstration of T cells with specificity to self-epitopes in vitro is not indicative for autoimmune disease. However, if at certain stages of infection such T cells are activated by crossreactive microbial epitopes they could cause autoimmune responses.  相似文献   

7.
Extracellular matrix metalloproteinase inducer (EMMPRIN) or CD147 is a transmembrane glycoprotein expressed by various cell types, including oral epithelial cells. Recent studies have brought evidence that EMMPRIN plays a role in periodontitis. In the present study, we investigated the effect of Porphyromonas gingivalis, a major pathogen in chronic periodontitis, on the shedding of membrane-anchored EMMPRIN and on the expression of the EMMPRIN gene by oral epithelial cells. A potential contribution of shed EMMPRIN to the inflammatory process of periodontitis was analyzed by evaluating the effect of recombinant EMMPRIN on cytokine and matrix metalloproteinase (MMP) secretion by human gingival fibroblasts. ELISA and immunofluorescence analyses revealed that P. gingivalis mediated the shedding of epithelial cell-surface EMMPRIN in a dose- and time-dependent manner. Cysteine proteinase (gingipain)-deficient P. gingivalis mutants were used to demonstrate that both Arg- and Lys-gingipain activities are involved in EMMPRIN shedding. Real-time PCR showed that P. gingivalis had no significant effect on the expression of the EMMPRIN gene in epithelial cells. Recombinant EMMPRIN induced the secretion of IL-6 and MMP-3 by gingival fibroblasts, a phenomenon that appears to involve mitogen activated protein kinases. The present study brought to light a new mechanism by which P. gingivalis can promote the inflammatory response during periodontitis.  相似文献   

8.
Adjuvant arthritis (AA) is induced by immunizing Lewis rats with Mycobacterium tuberculosis suspended in adjuvant. The mycobacterial 65-kDa heat shock protein (HSP65) contains at least one epitope associated with the pathogenesis of AA: T cell clones that recognize an epitope formed by aa 180-188 of HSP65 react with self-cartilage and can adoptively transfer AA. Nevertheless, vaccination with HSP65 or some of its T cell epitopes can prevent AA by a mechanism that seems to involve cross-reactivity with the self-60-kDa HSP60. We recently demonstrated that DNA vaccination with the human hsp60 gene can inhibit AA. In the present work, we searched for regulatory epitopes using DNA vaccination with HSP60 gene fragments. We now report that specific HSP60 DNA fragments can serve as effective vaccines. Using overlapping HSP60 peptides, we identified a regulatory peptide (Hu3) that was specifically recognized by the T cells of DNA-vaccinated rats. Vaccination with Hu3, or transfer of splenocytes from Hu3-vaccinated rats, inhibited the development of AA. Vaccination with the mycobacterial homologue of Hu3 had no effect. Effective DNA or peptide vaccination was associated with enhanced T cell proliferation to a variety of disease-associated Ags, along with a Th2/3-like shift (down-regulation of IFN-gamma secretion and enhanced secretion of IL-10 and/or tumor growth factor beta1) in response to peptide Mt176-190 (the 180-188 epitope of HSP65). The regulatory response to HSP60 or its Hu3 epitope included both Th1 (IFN-gamma) and Th2/3 (IL-10/tumor growth factor beta1) secretors. These results show that regulatory mechanisms can be activated by immunization with relevant self-HSP60 epitopes.  相似文献   

9.
We have used a recombinant approach to characterise the B- and T-cell epitopes of FanC, the major subunit polypeptide of K99 (F5) fimbriae of enterotoxigenic Escherichia coli strains. This involved the fusion of FanC and its carboxy-terminal truncated derivatives to a reporter, the E. coli alkaline phosphatase (PhoA), generating stable, recombinant fusions. The B-cell epitopes of FanC were characterised by Western blotting of FanC::PhoA fusion proteins with a polyclonal mouse antiserum directed against K99 fimbrial antigen, and with a panel of monoclonal antibodies generated to the K99 antigen. An attempt to characterise the T-cell epitopes of the fimbrial subunit was made by standard in vitro T-cell proliferation assay. Our results suggest that the B-cell epitopes of FanC are likely to be continuous, with a potentially immunodominant epitope at the carboxy-terminus. However, T-cell proliferation assays with the FanC::PhoA fusion proteins did not indicate any immunodominant T-cell epitope(s). We hypothesise that fusion of FanC peptides to PhoA had resulted in altered folding of the peptides for antibody and T-cell recognition, highlighting the potential problems and drawbacks of the recombinant fusion technique in defining the epitopes of certain proteins.  相似文献   

10.
We have characterized immunogenic epitopes of the 31-kDa outer surface protein A (OspA) protein of Borrelia burgdorferi, which is a major surface Ag of the spirochete causing Lyme disease. Full length and truncated forms of rOspA proteins were expressed in Escherichia coli, and their reactivities with antibodies and human T cell clones isolated from patients with Lyme disease were determined. The epitopes recognized by three of four OspA-reactive T cell clones are contained within the 60 COOH-terminal amino acids. Each of the four OspA-reactive T cell clones has a different HLA class II molecule involved in Ag recognition and recognizes a distinct epitope. One T cell clone promiscuously recognized an epitope in the context of different HLA-DQ molecules. In addition, the binding of a murine monoclonal anti-OspA antibody, as well as antibodies in sera of three of five patients with Lyme disease, was dependent upon the amino acids in the carboxy-terminal protion of this protein. Taken together, our results indicate that the 60 COOH-terminal amino acids of OspA contain epitopes recognized by human antibodies and T cells.  相似文献   

11.
Using synthetic peptides, we characterized the B-lymphocyte (antibody) and T-lymphocyte (proliferation) responses to an immunodominant epitope of human immunodeficiency virus type 1 (HIV-1) located near the amino-terminal end of the transmembrane glycoprotein (env amino acids 598 to 609). Both immunoglobulin M (IgM) and IgG antibodies against this epitope appeared early after primary infection with HIV-1. In an animal model, the IgG response to a synthetic peptide derived from this sequence was T-helper-cell dependent, whereas the IgM response was T-cell independent. In addition, antibody generated by immunization with this peptide had HIV-1-neutralizing activity. Greater than 99% (201 of 203) of patients infected with HIV-1 generated antibody to this peptide in vivo; however, only 24% (7 of 29) had T cells that proliferated in response to this peptide in vitro. These observations suggest that different HIV-1 gp41 epitopes elicit B-cell and T-cell immune responses.  相似文献   

12.
1. On Western blot analysis, serum IgG from a healthy human subject reacted with a stress-induced protein, having an apparent molecular mass of 70 kDa, from PC12 cells. 2. This serum IgG also reacted with hsp70 (70-kDa heat-shock protein) purified from the bovine brain. 3. In 5 out of 34 healthy human subjects, IgG antibodies against hsp70 were detected. 4. These antibodies were directed against the stress-inducible 72-kDa protein, but did not cross-react with the constitutive 73-kDa protein.  相似文献   

13.
GNA1870, a 28-kDa surface-exposed lipoprotein of Neisseria meningitidis recently discovered by reverse vaccinology, is one of the most potent antigens of Meningococcus and a promising candidate for a universal vaccine against a devastating disease. Previous studies of epitope mapping and genetic characterization identified residues critical for bactericidal response within the C-terminal domain of the molecule. To elucidate the conformation of protective epitopes, we used NMR spectroscopy to obtain the solution structure of the immunodominant 18-kDa C-terminal portion of GNA1870. The structure consists of an eight-stranded antiparallel beta-barrel overlaid by a short alpha-helix with an unstructured N-terminal end. Residues previously shown to be important for antibody recognition were mapped on loops facing the same ridge of the molecule. The sequence similarity of GNA1870 with members of the bacterial transferrin receptor family allows one to predict the folding of this class of well known bacterial antigens, providing the basis for the rational engineering of high affinity B cell epitopes.  相似文献   

14.
BackgroundThe VP1 protein of duck hepatitis A virus (DHAV) is a major structural protein that induces neutralizing antibodies in ducks; however, B-cell epitopes on the VP1 protein of duck hepatitis A genotype 1 virus (DHAV-1) have not been characterized.

Methods and Results

To characterize B-cell epitopes on VP1, we used the monoclonal antibody (mAb) 2D10 against Escherichia coli-expressed VP1 of DHAV-1. In vitro, mAb 2D10 neutralized DHAV-1 virus. By using an array of overlapping 12-mer peptides, we found that mAb 2D10 recognized phages displaying peptides with the consensus motif LPAPTS. Sequence alignment showed that the epitope 173LPAPTS178 is highly conserved among the DHAV-1 genotypes. Moreover, the six amino acid peptide LPAPTS was proven to be the minimal unit of the epitope with maximal binding activity to mAb 2D10. DHAV-1–positive duck serum reacted with the epitope in dot blotting assay, revealing the importance of the six amino acids of the epitope for antibody-epitope binding. Competitive inhibition assays of mAb 2D10 binding to synthetic LPAPTS peptides and truncated VP1 protein fragments, detected by Western blotting, also verify that LPAPTS was the VP1 epitope.

Conclusions and Significance

We identified LPAPTS as a VP1-specific linear B-cell epitope recognized by the neutralizing mAb 2D10. Our findings have potential applications in the development of diagnostic techniques and epitope-based marker vaccines against DHAV-1.  相似文献   

15.
Mouse monoclonal antibodies (mAbs) were developed against Streptococcus pneumoniae in search for potential common pneumococcal proteins as vaccine antigens. mAb 230,B-9 (IgG1) reacted by immunoblotting with a 70-kDa protein which was isolated by immunoaffinity chromatography and subsequent preparative electrophoresis. N-terminal amino acid sequencing showed homology to that of heat shock protein 70 (hsp70). The hsp70 epitope reactive with mAb 230,B-9 was found in all the pneumococci examined as well as in other streptococci and enterococci. The epitope was not expressed in several other examined Gram-positive or -negative bacteria. Pneumococcal hsp70 has by other investigators been proposed to be a vaccine candidate. Binding experiments using flow cytometry showed that the epitope was not surface-exposed on live exponential phase grown S. pneumoniae. Human patient sera did not react with affinity-purified pneumococcal hsp70. Therefore the pneumococcal hsp70 does not seem to be of special interest in a vaccine formulation. The human sera contained antibodies to high molecular proteins co-purified with hsp70. Some of these proteins could be the pneumococcal surface protein A.  相似文献   

16.
Serum antibody titers against the lipopolysaccharides (LPSs) of Porphyromonas gingivalis and Fusobacterium nucleatum were compared between 9 periodontitis patients and 24 healthy persons. The IgG titers against the LPSs of P. gingivalis ATCC 33277(T) and W50 were clearly higher in the patients than in the healthy persons. However, IgM titers against the LPSs of P. gingivalis strains were relatively low, and no significant difference was observed between the patients and healthy persons. On the other hand, IgG and IgM titers against the LPS of Fusobacterium nucleatum JCM 8532(T) in some patients were significantly higher than those in the healthy persons, although the difference in IgG titers was not large compared to that of the LPS of P. gingivalis. These results suggest that the antibody measurement of patients' sera against the LPS of periodontal bacteria can be applied for the diagnosis of periodontitis.  相似文献   

17.
Sub-unit vaccines are synthetic or recombinant peptides representing T- or B-cell epitopes of major protein antigens from a particular pathogen. Epitope selection requires the synthesis of peptides that overlap the protein sequences and screening for the most effective ones. In this study a new method of immunogenic peptide selection based on the analysis of information structure of protein sequences is suggested. The analysis of known B-cell epitope location in the information structure of Aspergillus fumigatus proteins Asp f 2 and Asp f 3 has shown that epitopes are scattered along the sequences of proteins for the exception of sites with Increased Degree Information Coordination (IDIC). Based on these results peptides from different allergens such as Asp f 2, Der p 1, and Fel d 1 were selected and produced in a recombinant form in the context of yeast virus-like particles (VLPs). Immunization of mice with VLPs containing peptides form allergens has induced the production of IgG able to recognize full-length antigens. This result suggests that the analysis of information structure of proteins can be used for the selection of peptides possessing cryptic B-cell epitope activity.  相似文献   

18.
Abstract The aim of this study was to determine whether lipid A-associated proteins (LAP) from two periodontopathogenic species of bacteria were able to stimulate interleukin-6 (IL-6) release from human gingival fibroblasts and myelomonocytic cells. LAP and lipopolysaccharide (LPS) were extracted from Porphyromonas gingivalis and Prevotella intermedia and added to cultures of human gingival fibroblasts and mono-mac-6 monocytic cells. Release of IL-6 into the culture supermatants was determined by ELISA. LAP and LPS from Por. gingivalis , but not from Prev. intermedia , stimulated IL-6 release from both cell types in a dose-dependent manner although LPS was less potent than LAP in inducing IL-6 release from the fibroblasts. IL-6 was detectable in cultures of both cell types following stimulation with LAP from Por. gingivalis at a concentration as low as 10 ng/ml. In response to LAP from Prev. intermedia , IL-6 was produced by mono-mac-6 cells but not by fibroblasts. Our results show that bacterial cell wall components other than LPS can induce IL-6 release from cells of the periodontium in vitro. The production of such potent immunomodulatory agents in vivo may contribute to the connective tissue breakdown characteristic of chronic periodontitis.  相似文献   

19.
Enterovirus A71 (EV-A71) is one of the main causative agents of hand, foot and mouth disease (HFMD). Unlike other enteroviruses that cause HFMD, EV-A71 is more frequently associated with severe neurological complications and fatality. To date, no effective licensed antivirals are available to combat EV-A71 infection. Little is known about the immunogenicity of viral non-structural proteins in humans. Previous studies have mainly focused on characterization of epitopes of EV-A71 structural proteins by using immunized animal antisera. In this study, we have characterized human antibody responses against the structural and non-structural proteins of EV-A71. Each viral protein was cloned and expressed in either bacterial or mammalian systems, and tested with antisera by western blot. Results revealed that all structural proteins (VP1-4), and non-structural proteins 2A, 3C and 3D were targets of EV-A71 IgM, whereas EV-A71 IgG recognized all the structural and non-structural proteins. Sixty three synthetic peptides predicted to be immunogenic in silico were synthesized and used for the characterization of EV-A71 linear B-cell epitopes. In total, we identified 22 IgM and four IgG dominant epitopes. Synthetic peptide PEP27, corresponding to residues 142–156 of VP1, was identified as the EV-A71 IgM-specific immunodominant epitope. PEP23, mapped to VP1 41–55, was recognized as the EV-A71 IgG cross-reactive immunodominant epitope. The structural protein VP1 is the major immunodominant site targeted by anti-EV-A71 IgM and IgG antibodies, but epitopes against non-structural proteins were also detected. These data provide new understanding of the immune response to EV-A71 infection, which benefits the development of diagnostic tools, potential therapeutics and subunit vaccine candidates.  相似文献   

20.
Orientia tsutsugamushi, a cause of scrub typhus is emerging as an important pathogen in several parts of the tropics. The control of this infection relies on rapid diagnosis, specific treatment, and prevention through vector control. Development of a vaccine for human use would be very important as a public health measure. Antibody and T-cell response have been found to be important in the protection against scrub typhus. This study was undertaken to predict the peptide vaccine that elicits both B- and T-cell immunity. The outer-membrane protein, 47-kDa high-temperature requirement A was used as the target protein for the identification of protective antigen(s). Using BepiPred2 program, the potential B-cell epitope PNSSWGRYGLKMGLR with high conservation among O. tsutsugamushi and the maximum surface exposed residues was identified. Using IEDB, NetMHCpan, and NetCTL programs, T-cell epitopes MLNELTPEL and VTNGIISSK were identified. These peptides were found to have promiscuous class-I major histocompatibility complex (MHC) binding affinity to MHC supertypes and high proteasomal cleavage, transporter associated with antigen processing prediction, and antigenicity scores. In the I-TASSER generated model, the C-score was −0.69 and the estimated TM-score was 0.63 ± 0.14. The location of the epitope in the 3D model was external. Therefore, an antibody to this outer-membrane protein epitope could opsonize the bacterium for clearance by the reticuloendothelial system. The T-cell epitopes would generate T-helper function. The B-cell epitope(s) identified could be evaluated as antigen(s) in immunodiagnostic assays. This cocktail of three peptides would elicit both B- and T-cell immune response with a suitable adjuvant and serve as a vaccine candidate.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号