Chlamydia Trachomatis Protein Research Articles

Poly(lactic acid)–poly(ethylene glycol) nanoparticles provide sustained delivery of a Chlamydia trachomatis recombinant MOMP peptide and potentiate systemic adaptive immune responses in mice

PLA–PEG [poly(lactic acid)–poly (ethylene glycol)], a biodegradable copolymer, is underexploited for vaccine delivery although it exhibits enhanced biocompatibility and slow release immune-potentiating properties. We document here successful encapsulation of M278, a Chlamydia trachomatis MOMP (major outer-membrane protein) peptide, within PLA–PEG nanoparticles by size (~73-100nm), zeta potential (−16mV), smooth morphology, encapsulation efficiency (~60%), slow release pattern, and non-toxicity to macrophages. Immunization of mice with encapsulated M278 elicited higher M278-specific T-cell cytokines [Th1 (IFN-γ, IL-2), Th17 (IL-17)] and antibodies [Th1 (IgG2a), Th2 (IgG1, IgG2b)] compared to bare M278. Encapsulated-M278 mouse serum inhibited Chlamydia infectivity of macrophages, with a concomitant transcriptional down-regulation of MOMP, its cognate TLR2 and CD80 co-stimulatory molecule. Collectively, encapsulated M278 potentiated crucial adaptive immune responses, which are required by a vaccine candidate for protective immunity against Chlamydia. Our data highlight PLA–PEG's potential for vaccines, which resides in its slow release and potentiating effects to bolster immune responses. From the Clinical EditorThis study highlights the potential of a PLA-PEG-based nanoparticle formulation containing a major outer membrane protein of chlamydia trachomatis in inducing a sustained enhanced immune response, paving the way to the development of a vaccination strategy against this infection.

Functional Analysis of Hypothetical Proteins of Chlamydia Trachomatis: A Bioinformatics Based Approach for Prioritizing the Targets

The various genome sequencing projects have led to the accumulation of entire set of gene sequences of many organisms. Among the sequenced genomes are numerous genes which code for proteins of unknown function. These genes are termed as hypothetical genes and their corresponding gene products are known as Hypothetical Proteins (HPs). Analyzing and annotating the functions of these HPs is important in pathogenic organisms such as Chlamydia trachomatis that causes various sequelae of diseases by infecting different sites in humans. Functional annotations of these HPs provides insights into their exact molecular function and may help in identification of novel drug or vaccine candidates for the control of infections caused by C. trachomatis. In the present study, entire set of 336 HPs of C. trachomatis were retrieved from NCBI and analyzed for their function using bioinformatics tools such as CDD-BLAST, PFAM, TIGRFAM and SCANPROSITE. The analysis revealed that some of the HPs possessed functionally important domains like protease, ligase, synthase, translocase and zinc finger domain. Some of the hypothetical proteins were found to be similar to transcriptional regulators while others were homologous to chaperonins. A few of the HPs corresponded to the bacterial secretory pathway proteins. The structural prediction of the annotated proteins has been performed which further substantiate the functional characterization results. Bioinformatics approach used in this study, including sophisticated sequence analysis, domain characterization and structural prediction studies, can provide a useful lead to experimentally annotate and corroborate these studies. Data generated by this study might facilitate swift identification of potential therapeutic targets and thereby enabling the search for new inhibitors or vaccines.

Detection of antibodies against immunodominant proteins of Chlamydia trachomatis in the sera of patients with urogenital Chlamydia trachomatis infection

Objective To detect antibodies against chlamydial plasmid-encoded protein 3 (Pgp3),outer membrane complex protein B C-terminal peptide (OmcBc),CT841 protein and heat shock protein 60 (HSP60) in the sera of patients with urogenital Chlamydia trachomatis infection.Methods Recombinant plasmids encoding the aforementioned four proteins and an empty plasmid were transformed into Escherichia coli separately followed by 2-hour isopropyl-1-thio-β-galactopyranoside (IPTG) induction and cell lysis.The expressed proteins were purified with glutathione magnetic beads and then used to coat 96-well enzyme-linked immunosorbent assay (ELISA) plates precoated by glutathione.Serum samples were collected from 20 patients with and 20 clients without urogenital C.trachomatis infection attending the sexually transmitted disease (STD) clinic of Tianjin Medical University General Hospital.ELISA with the expressed protein-coated plates was adopted to detect antibodies against these proteins in the serum samples.Results Of the 20 serum samples from C.trachomatis-infected patients,14 (70％)had anti-Pgp3 antibody,9 (45％) anti-OmcBc antibody,8 (40％) anti-CT841 antibody,and 5 (25％) anti-HSP60 antibody.Meanwhile,no antibody was detected in any of the serum samples from uninfected clients except for one with anti-HSP60 antibody.Conclusions Of the four studied C.trachomatis proteins,Pgp3 appears to have the strongest antigenicity with the highest antibody-detection rate,while HSP60 exhibits the weakest antigenicity with the lowest antibody-detection rate. Key words: Chlamydia trachomatis; Chaperonin 60; Pgp3; OmcB; CT841

Development of ELISAs for the Detection of Urogenital Chlamydia trachomatis Infection Targeting the pORF5 Protein

ObjectiveTo prepare antibodies against pORF5 plasmid protein of Chlamydia trachomatis and develop double-antibody sandwich enzyme-linked immunosorbent assays (DAS-ELISAs) for the detection of genital C. trachomatis infections. MethodsThe pORF5 protein was expressed in Escherichia coli and used to immunize BALB/c mice and New Zealand rabbits to produce monoclonal antibodies (mAbs) and polyclonal antibody (pAb) for DAS-ELISAs. Clinical samples from 186 urogenital infection patients (groups I) and 62 healthy donors (groups II) were detected in parallel by the DAS-ELISAs developed in this study and by IDEIA PCE commercial ELISA. ResultsTwo hybridoma cell lines, named 2H4 and 4E6, stably secreting specific mAbs against pORF5 were obtained. The mAb 2H4 was recognized by 32 (17.20%, positive recognition rate) and 25 (13.44%), mAb 2H4 by 0 (0%) and 2 (3.22%) samples from groups I and II, respectively. The sensitivities of mAbs 2H4 and 4E6 were 92.11% and 77.78% and the specificities were 100% and 96.88%, respectively in relation to the IDEIA PCE commercial ELISA. The sensitivities of detection for the DAS-ELISAs were 10 ng/mL (based on 2H4) and 18 ng/mL (based on 4E6). ConclusionTwo DAS-ELISAs were developed in this study that provided a feasible and effective assay that could be considered alternative tools for the serodiagnosis of C. trachomatis infection.

PORF5 plasmid protein of Chlamydia trachomatis induces MAPK-mediated pro-inflammatory cytokines via TLR2 activation in THP-1 cells

Infection with Chlamydia trachomatis induces inflammatory pathologies in the urogenital tract that can lead to infertility and ectopic pregnancy. Pathogenesis of infection has been mostly attributed to excessive cytokine production. However, precise mechanisms on how C. trachomatis triggers this production, and which protein(s) stimulate inflammatory cytokines remains unknown. In the present study, the C. trachomatis pORF5 protein induced tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β) and interleukin-8 (IL-8) in dose- and time-dependent manners in the THP-1 human monocyte cell line. We found that intracellular p38/mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK)/MAPK signaling pathways were required for the induction of TNF-α, IL-1β and IL-8. Blockade of toll-like receptor 2 (TLR2) signaling reduced induction levels of TNF-α, IL-8 and IL-1β. We concluded that the C. trachomatis pORF5 protein might contribute to the inflammatory processes associated with chlamydial infections.

IgG subclass profiles in normal human sera of antibodies specific to five kinds of microbial antigens

The levels of subclass-specific immunoglobulin G (IgG) antibodies to five microbial antigens in normal human sera were measured by enzyme-linked immunosorbent assays (ELISA). The aim was to compare the IgG subclass profiles of specific antibodies to diverse antigens originating from virus, intra- and extracellular bacteria. Serum samples from 162 Danish women were analyzed for IgG1, IgG2, IgG3, and IgG4 antibodies against a peptide of the major outer membrane protein (MOMP) of Chlamydia trachomatis, the native outer membrane proteins of Chlamydia pneumoniae, recombinant membrane proteins of Mycoplasma pneumoniae, recombinant parvovirus B19 capsomers (VP1 and VP2) and C-polysaccharide of Streptococcus pneumoniae (pneumococcus). Antibodies specific for viral and bacterial protein antigens belonged mainly to the subclasses IgG1 and IgG3 while the antibody profile specific for pneumococcal C-polysaccharide was dominated by the subclass IgG2. Antibodies to virus, intra- and extracellular bacteria entering the body via the respiratory tract were found primarily to elicit an IgG1 response. In contrast, antibodies specific for MOMP from C.trachomatis, which infects the urogenital tract, were predominantly IgG3. Our results show that the nature of the antigen and/or the site of colonization or infection have impact on which type of IgG subclass a microorganism elicits.

Chlamydia trachomatis recombinant MOMP encapsulated in PLGA nanoparticles triggers primarily T helper 1 cellular and antibody immune responses in mice: a desirable candidate nanovaccine

We recently demonstrated by in vitro experiments that PLGA (poly D, L-lactide-co-glycolide) potentiates T helper 1 (Th1) immune responses induced by a peptide derived from the recombinant major outer membrane protein (rMOMP) of Chlamydia trachomatis, and may be a promising vaccine delivery system. Herein we evaluated the immune-potentiating potential of PLGA by encapsulating the full-length rMOMP (PLGA-rMOMP), characterizing it in vitro, and investigating its immunogenicity in vivo. Our hypothesis was that PLGA-rMOMP triggers Th1 immune responses in mice, which are desirable prerequisites for a C. trachomatis candidate nanovaccine. Physical-structural characterizations of PLGA-rMOMP revealed its size (approximately 272 nm), zeta potential (−14.30 mV), apparent spherical smooth morphology, and continuous slow release pattern. PLGA potentiated the ability of encapsulated rMOMP to trigger production of cytokines and chemokines by mouse J774 macrophages. Flow cytometric analyses revealed that spleen cells from BALB/c mice immunized with PLGA-rMOMP had elevated numbers of CD4+ and CD8+ T cell subsets, and secreted more rMOMP-specific interferon-gamma (Th1) and interleukin (IL)-12p40 (Th1/Th17) than IL-4 and IL-10 (Th2) cytokines. PLGA-rMOMP-immunized mice produced higher serum immunoglobulin (Ig)G and IgG2a (Th1) than IgG1 (Th2) rMOMP-specific antibodies. Notably, sera from PLGA-rMOMP-immunized mice had a 64-fold higher Th1 than Th2 antibody titer, whereas mice immunized with rMOMP in Freund’s adjuvant had only a four-fold higher Th1 than Th2 antibody titer, suggesting primarily induction of a Th1 antibody response in PLGA-rMOMP-immunized mice. Our data underscore PLGA as an effective delivery system for a C. trachomatis vaccine. The capacity of PLGA-rMOMP to trigger primarily Th1 immune responses in mice promotes it as a highly desirable candidate nanovaccine against C. trachomatis.

The Manganese Ion of the Heterodinuclear Mn/Fe Cofactor in Chlamydia trachomatis Ribonucleotide Reductase R2c Is Located at Metal Position 1

The essential catalytic radical of Class-I ribonucleotide reductase is generated and delivered by protein R2, carrying a dinuclear metal cofactor. A new R2 subclass, R2c, prototyped by the Chlamydia trachomatis protein was recently discovered. This protein carries an oxygen-activating heterodinuclear Mn(II)/Fe(II) metal cofactor and generates a radical-equivalent Mn(IV)/Fe(III) oxidation state of the metal site, as opposed to the tyrosyl radical generated by other R2 subclasses. The metal arrangement of the heterodinuclear cofactor remains unknown. Is the metal positioning specific, and if so, where is which ion located? Here we use X-ray crystallography with anomalous scattering to show that the metal arrangement of this cofactor is specific with the manganese ion occupying metal position 1. This is the position proximal to the tyrosyl radical site in other R2 proteins and consistent with the assumption that the high-valent Mn(IV) species functions as a direct substitute for the tyrosyl radical.

A novel chimeric MOMP antigen expressed in Escherichia coli, Arabidopsis thaliana, and Daucus carota as a potential Chlamydia trachomatis vaccine candidate

The major outer membrane protein (MOMP) of Chlamydia trachomatis is a highly antigenic and hydrophobic transmembrane protein. Our attempts to express the full-length protein in a soluble form in Escherichia coli and in transgenic plants failed. A chimeric gene construct of C. trachomatis serovar E MOMP was designed in order to increase solubility of the MOMP protein but with retained antigenicity. The designed construct was successfully expressed in E. coli, in Arabidopsis thaliana, and in Daucus carota. The chimeric MOMP expressed in and purified from E. coli was used as antigen for production of antibodies in rabbits. The anti-chimeric MOMP antibodies recognized the corresponding protein in both E. coli and in transgenic plants, as well as in inactivated C. trachomatis elementary bodies. Transgenic Arabidopsis and carrots were characterized for the number of MOMP chimeric genetic inserts and for protein expression. Stable integration of the transgene and the corresponding protein expression were demonstrated in Arabidopsis plants over at least six generations. Transgenic carrots showed a high level of expression of the chimeric MOMP – up to 3% of TSP.

Evaluation of a broadly protective Chlamydia–cholera combination vaccine candidate

The need to simultaneously target infections with epidemiological overlap in the population with a single vaccine provides the basis for developing combination vaccines. Vibrio cholerae ghosts (rVCG) offer an attractive approach for developing vaccines against a number of human and animal pathogens. In this study, we constructed a multisubunit vaccine candidate co-expressing the serovar D-derived Porin B and polymorphic membrane protein-D proteins of Chlamydia trachomatis and evaluated its ability to simultaneously induce broad-based chlamydial immunity and elicit a vibriocidal antibody response to the Vibrio carrier envelope. Intramuscular (IM) immunization with the vaccine candidate elicited high levels of antigen-specific genital mucosal and systemic Th1 cell-mediated and humoral immune responses against heterologous serovars and strains, including serovars E–H and L. Also, in addition to the multisubunit vaccine, the single subunit constructs conferred significant cross protection against the heterologous mouse strain, Chlamydia muridarum. Furthermore, all mice immunized with rVCG vaccine constructs responded with a significant rise in vibriocidal antibody titer, the surrogate marker for protection in cholera. These findings demonstrate the ability of the multisubunit vaccine to induce cross protective chlamydial as well as vibriocidal immunity and establish the possibility of developing a broadly efficacious Chlamydia–cholera combination vaccine.

A Peptide Containing T-Cell Epitopes of <i>Chlamydia trachomatis</i> Recombinant MOMP Induces Systemic and Mucosal Antibody Responses in Mice

We reported that intranasal immunization of mice with recombinant major outer membrane protein (MOMP) of Chlamydia trachomatis genetically fused with modified cholera toxin elicited mucosal and systemic antibody responses, but with inefficient protective mechanisms for complete protection of mice against a homologous C. trachomtis challenged infection. To begin to identify specific immunogenic MOMP regions to pursue as vaccine candidates, herein we selected small gene fragments of the MOMP gene containing T-cell epitopes (278-370 aa) and generated a rMOMP peptide (rMOMP-278). rMOMP and rMOMP-278 proteins were cloned, expressed, and their purities and specificities confirmed by SDS-PAGE and Western blot, respectively. We tested the immunogenicity of rMOMP-278 as compared to the parent rMOMP in mice. Mice were immunized intramuscularly with purified rMOMP proteins; total- and isotype- (IgA, IgG1, IgG2a, and IgG2b) specific antibodies in sera and vaginal washes were measured by ELISA. Immunized mice developed antigen-specific total antibodies in a kinetic fashion, with responses being higher to rMOMP than rMOMP- 278. However, antigen-specific isotype antibodies were detected in the order of IgG2b > IgG2a > IgG1 for rMOMP- 278, indicating more of a mixed Th1/Th2 response. Contrastingly, antibody responses to rMOMP was more of a predominant Th2 response in the order of IgG1 > IgG2b > IgG2a. Our data are evidence to suggest that rMOMP-278 is immunogenic by its ability to evoke systemic and mucosal immune responses with a Th1 bias in mice, and therefore may be an attractive peptide alternative to full MOMP as a vaccine candidate against C. trachomatis genital tract infection.

Induction of immune memory by a multisubunit chlamydial vaccine

We tested the hypothesis that intramuscular immunization with a multisubunit chlamydial vaccine candidate will induce long lasting immune responses in mice. Accordingly, groups of female C57BL/6 mice were immunized intramuscularly with Vibrio cholerae ghosts (VCG) expressing the Poring B and polymorphic membrane protein-D proteins of Chlamydia trachomatis or a control antigen. Humoral and cell-mediated immune responses were evaluated following immunization and after live chlamydial infection. Immunization induced an anamnestic response characterized by chlamydial-specific IgG2a and IgA antibodies in sera and vaginal lavage as well as specific genital and splenic T cell responses. The results also revealed that the local mucosal and systemic cellular and humoral immune effectors induced in mice following immunization with the vaccine candidate are long lasting. Vaccinated mice cleared intravaginal challenge with 105 chlamydial inclusion forming units within 12 days compared to control mice, which shed up to 2×103IFUs at this time point. Moreover, rechallenge of mice 98 days after resolution of the primary infection resulted in the recall and retention of a relatively high frequency of chlamydial-specific Th1 cells and IgG2a in the genital mucosa. These results provide the first evidence that a VCG-based multisubunit chlamydial vaccine is capable of effectively stimulating anamnestic systemic and mucosal immune responses in mice. The data support further vaccine evaluation and testing for induction of long-term protective immunity.

Modulation of pro-inflammatory mediators by IL-10 in mouse J774 macrophages stimulated with rMOMP-498 of Chlamydia trachomatis (37.5)

Abstract We have recently constructed several recombinant major outer membrane proteins (rMOMP) of Chlamydia trachomatis, as potential vaccine candidates. In vitro characterization of the rMOMP-498 (gene fragment corresponding to amino acids 187-344) revealed that it stimulated the production of IL-6, IL-12p40, IL-1β, TNF-α and IL-10 in mouse J774 macrophages. Since IL-10 is a modulator of macrophage activities, we hypothesized that IL-10 induced by rMOMP-498 in macrophages may serve to control inflammation during the initial phase of a C. trachomatis infection. To address our hypothesis we added exogenous mouse IL-10 to J774 cells stimulated with rMOMP-498. IL-10 decreased the production of IL-6, IL12p40 and TNF-α in these cells. Removal of endogenous IL-10 with neutralizing anti-IL-10 Ab in cultures stimulated with rMOMP-498 in part increased the levels of inflammatory mediators as compared to the control Ab. Analyses of CD80, TLR2, TLR4, and CD86 receptors on cells stimulated with rMOMP-498 alone or combined with IL-10 showed no differences in receptor expression levels between the stimulants, suggesting that these receptors are not involved in the IL-10 down-regulatory activities in rMOMP-498-stimulated macrophages. Overall, our data show that IL-10 may be important in the innate immune response to rMOMP-498 as a vaccine candidate. Current studies are underway to identify the mechanism of IL-10 control of the inflammatory response in macrophages.

Scanning diagnostically significant antigenic regions of major Chlamydia Trachomatis protein MOMP using series of overlapping recombinant proteins

The amino acid sequence of the Chlamydia trachomatis major outer membrane protein (MOMP) has been modeled using a series of recombinant proteins containing MOMP fragments with lengths of 100 amino acids and overlaps of 30 amino acids. Testing of recombinant antigens in the immune enzyme analysis has shown that the proteins containing MOMP fragments of 191–286 and from 191–354 amino acids have had the greatest activity in the reaction with the anti-C. trachomatis-positive sera. The obtained data allow us to reach conclusions regarding the possibility of applying the presented recombinant proteins to develop a diagnostic test for detecting anti-C. trachomatis antibodies.

The Natural History of Trachoma Infection and Disease in a Gambian Cohort with Frequent Follow-Up

BackgroundThe natural history of ocular Chlamydia trachomatis infections in endemic communities has not been well characterised and is an important determinant of the effectiveness of different mass treatment strategies to prevent blindness due to trachoma.Methodology/Principal FindingsA multistate hidden Markov model was fitted to data on infection and active disease from 256 untreated villagers in The Gambia who were examined every 2 weeks over a 6-month period. Parameters defining the natural history of trachoma were estimated, and associations between these parameters, demographic and baseline immune measurements examined. The median incubation period following infection was estimated at 17 days (95% confidence interval: 11–28). Disease persisted for longer than infection (median 21 (15–32) weeks) versus 17 (12–24) weeks), with an estimated median duration of post-infection inflammation of 5 (3–8) weeks. The duration of active disease showed a significant decline with age even after accounting for lower rates of re-infection and disease at older ages (p = 0.004). Measurements of levels of baseline IgA to epitopes in the major outer membrane protein of Chlamydia trachomatis were not significantly correlated with protection or more rapid clearance of infection.ConclusionsThe average duration of infection with Chlamydia trachomatis especially at younger ages is long. This contributes to the persistence and gradual return of trachoma after community-wide treatment with antibiotics.

Autoimmune response to Chlamydia trachomatis infection and in vitro fertilization outcome

This observational study was conducted in 235 patients undergoing IVF who had a cervical swab positive for Chlamydia trachomatis and who underwent antibiotic treatment until a negative cervical swab before IVF attempt. After oocyte retrieval, follicular fluids of 109 patients out of 228 still showed the presence of IgA antichlamydia antibodies and a significantly lower pregnancy and implantation rate; therefore we conclude that patients should undergo IVF procedure after serum antichlamydia IgA tests negative.

Bioinformatic and biochemical evidence for the identification of the type III secretion system needle protein of Chlamydia trachomatis.

Chlamydia spp. express a functional type III secretion system (T3SS) necessary for pathogenesis and intracellular growth. However, certain essential components of the secretion apparatus have diverged to such a degree as to preclude their identification by standard homology searches of primary protein sequences. One example is the needle subunit protein. Electron micrographs indicate that chlamydiae possess needle filaments, and yet database searches fail to identify a SctF homologue. We used a bioinformatics approach to identify a likely needle subunit protein for Chlamydia. Experimental evidence indicates that this protein, designated CdsF, has properties consistent with it being the major needle subunit protein. CdsF is concentrated in the outer membrane of elementary bodies and is surface exposed as a component of an extracellular needle-like projection. During infection CdsF is detectable by indirect immunofluorescence in the inclusion membrane with a punctuate distribution adjacent to membrane-associated reticulate bodies. Biochemical cross-linking studies revealed that, like other SctF proteins, CdsF is able to polymerize into multisubunit complexes. Furthermore, we identified two chaperones for CdsF, termed CdsE and CdsG, which have many characteristics of the Pseudomonas spp. needle chaperones PscE and PscG, respectively. In aggregate, our data are consistent with CdsF representing at least one component of the extended Chlamydia T3SS injectisome. The identification of this secretion system component is essential for studies involving ectopic reconstitution of the Chlamydia T3SS. Moreover, we anticipate that CdsF could serve as an efficacious target for anti-Chlamydia neutralizing antibodies.

Predicted Epitomes of Outer Membrane Protein of Chlamydia Trachomatis by Bioinformatics Method: a Clue for Further Vaccine Development

Chlamydia Trachomatis infection is an important sexually transmitted disease for review. Development and approval of new vaccines are the hope for infectious control of the possible emerging pandemic of this pathogen. The outer membrane protein of Chlamydia Trachomatis may have value as a protective immunogen in novel vaccines. This study reports preliminary data from the computation analysis of outer membrane protein to find potential B-cell epitomes using a new bioinformatics tool. The possible alternatives are reported. According to this investigation, 41SCSDCGTCTSCAEATT56 is the peptide with the best binding affinity. These data are useful for further vaccine development because these promiscuous peptide binders allows the minimization of the total number of predicted epitomes without compromising the population coverage required in the design of vaccines.

Chlamydia trachomatis OmcB protein is a surface-exposed glycosaminoglycan-dependent adhesin

The OmcB protein of Chlamydia trachomatis is a cysteine-rich outer membrane polypeptide with important functional, structural and antigenic properties. The entire gene encoding the OmcB protein from C. trachomatis serovar LGV1 was cloned and expressed in Escherichia coli and the full-length protein used to raise polyclonal antibodies. Recombinant OmcB was used to show that OmcB is a surface-exposed protein that functions as a chlamydial adhesin. Infectivity inhibition assays carried out using HeLa cells with serovar LGV1 in the presence of purified anti-OmcB serum showed inhibition of infectivity, suggesting that some of the OmcB was surface exposed. Moreover, using recombinant OmcB in infectivity inhibition assays resulted in 70% inhibition of infectivity, confirming that OmcB plays a role as an adhesin in C. trachomatis. Furthermore, recombinant OmcB protein bound to the surface of HeLa and Hec1B cells, but binding to glycosaminoglycan (GAG)-deficient cells (pgsA-745 and pgsD-677) was markedly reduced, indicating that OmcB binds to GAG-like receptors on host cells.

Chlamydia trachomatis and chlamydial heat shock protein 60-specific antibody and cell-mediated responses predict tubal factor infertility

To evaluate the role of Chlamydia trachomatis-induced humoral and cell-mediated immune (CMI) responses in predicting tubal factor infertility (TFI). Blood samples were taken from 88 women with TFI and 163 control women. C. trachomatis and chlamydial heat shock protein 60 (CHSP60)-specific immunoglobulin G (IgG) antibodies were analysed using enzyme-linked immunosorbent assay (ELISA) kits. Proliferative reactivity of peripheral blood mononuclear cells was studied in vitro against Chlamydia elementary body (EB) and recombinant CHSP60 antigens. C. trachomatis-specific IgG antibodies were found more frequently (43.2 versus 13.5%), and the antibody levels were higher in the TFI cases than in the controls (P < 0.001). C. trachomatis EB-induced lymphocyte responses were positive in 81.8% of the TFI cases and 58.9% of the controls (P < 0.001). Similarly, CHSP60-induced lymphocyte responses were found in 45.5% of the TFI cases and 30.7% of the controls (P < 0.001). CHSP60 antibody test was the best single test predicting TFI. Compared to cases with all four markers negative, the estimated risk for TFI was 4.1 (95% CI 1.4-11.9) among those with one positive marker and 19.9 (95% CI 6.9-57.4) among those with three to four positive markers. Our results show that TFI prediction model can be improved by combining tests for humoral and CMI response to chlamydial antigens.