Frequency of Chlamydia trachomatis-specific T cell interferon-γ and interleukin-17 responses in CD4-enriched peripheral blood mononuclear cells of sexually active adolescent females

An evaluation of CD4 T cell responses to candidate Chlamydia trachomatis vaccine antigens was conducted in an adolescent female cohort exposed through natural infection to explore antigen immunogenicity and correlation with protection from reinfection. The frequency of peripheral blood CD4 T cell IFN-γ and IL-17 responses to three candidate vaccine antigens, polymorphic membrane protein G (PmpG), F (PmpF), and major outer membrane protein (MOMP), were determined by ELISPOT; responses to chlamydial heat shock protein 60 (HSP60) and to elementary bodies (EB) were included for comparison. Responses of Infected (n=8), Seropositive/Uninfected (n=13), and Seronegative/Uninfected (n=18) participants were compared. The median CD4 IFN-γ response to EB was significantly increased in Infected (P=0.003) and Seropositive/Uninfected (P=0.002) versus Seronegative/Uninfected female subjects. Higher rates of positive IFN-γ responders to EB, PmpF, and MOMP were detected in Seropositive/Uninfected versus Seronegative/Uninfected participants (P=0.021). IL-17 responses were generally low. A positive IFN-γ response to any of the antigens tested was associated with a trend toward a reduced risk of reinfection, although not statistically significant. Among this adolescent cohort, chlamydial-specific CD4 IFN-γ but not IL-17 responses were detected in acutely and previously infected participants and a positive CD4 IFN-γ response was associated with a non-significant reduced risk of reinfection.

Variability of genes encoding surface proteins used as vaccine antigens in meningococcal endemic and epidemic strain panels from Norway

Surface-expressed protein antigens such as factor H-binding protein (fHbp), Neisserial adhesin A (NadA), Neisserial heparin-binding antigen (NHBA) and Porin protein A (PorA); all express sequence variability that can affect their function as protective immunogens when used in meningococcal serogroup B vaccines like the recently-approved 4CMenB (Bexsero(®)). We assessed the sequence variation of genes coding for these proteins and two additional proteins ("fusion partners" to fHbp and NHBA) in pathogenic isolates from a recent low incidence period (endemic situation; 2005-2006) in Norway. Findings among strains from this panel were contrasted to what was found among isolates from a historic outbreak (epidemic situation; 1985-1990). Multilocus sequence typing revealed 14 clonal complexes (cc) among the 66 endemic strains, while cc32 vastly predominated in the 38-strain epidemic panel. Serogroup B isolates accounted for 50/66 among endemic strains and 28/38 among epidemic strains. Potential strain-coverage ("sequence match") for the 4CMenB vaccine was identified among the majority (>70%) of the endemic serogroup B isolates and all of the epidemic serogroup B isolates evaluated. Further information about the degree of expression, surface availability and the true cross-reactivity for the vaccine antigens will be needed to fully characterize the clinical strain-coverage of 4CMenB in various geographic and epidemiological situations.

[An indirect ELISA using Legionella pneumophila recombinant MOMP protein and its application in serological diagnosis]

OBJECTIVE

To express and purify the recombinant major outer membrane protein (MOMP) of Legionella pneumophila (Lp) as diagnostic antigen, and explore its practical value in the serological diagnosis of Lp infection.

METHODS

The recombinant plasmid pET-momp was transformed into the E.coli BL21 competent cells. The recombinant MOMP was induced to express, and then analyzed by SDS-PAGE electrophoresis, purified by affinity chromatography. We screened and obtained 58 positive blood serum and 32 negative blood serum using the DRG (Germany, IgG/IgM/IgA) Lp kit. The blood serum samples were detected for IgG, IgM, IgA antibody levels by indirect ELISA that we had established with the purified MOMP as the coating antigen, as well as by R&D (USA, IgG/IgM/IgA) Lp kit. Then using the receiver operating characteristic (ROC) curve, we compared these two methods in the sensitivity, specificity and consistency of the test results, for evaluating the application value of the indirect ELISA of recombinant MOMP.

RESULTS

The approximately 45 000 recombinant MOMP was successfully expressed and purified. Compared with the indirect ELISA we established with the R&D Lp kit for detecting Lp antibody IgG, IgM and IgA in blood serum, the sensitivity of the indirect ELISA of recombinant MOMP to IgG was 90.9%, the specificity was 91.7%, the Kappa value was 0.784 (P < 0.05), and the area under the ROC curve was 0.913; the sensitivity to IgM was 91.4% and the specificity was 90.6%, the Kappa value was 0.809 (P < 0.05), and the area under the ROC curve was 0.910; the sensitivity to IgA was 92.1% and the specificity was 88.9%, the Kappa value was 0.793(P < 0.05), and the area under the ROC curve was 0.905.

CONCLUSION

The recombinant MOMP was successfully induced to express and purified. The indirect ELISA we established with the recombinant MOMP protein as a diagnostic antigen showed good specificity, sensitivity and consistency, which laid a foundation for the development of serological diagnosis kit of Legionnaires' disease.

Targeting tissular immune response improves diagnostic performance of anti-Saccharomyces cerevisiae antibodies (ASCA) in Crohn's disease

Antibodies against Saccharomyces cerevisiae (ASCA) and Escherichia coli outer membrane porin C (anti-OmpC) are known to be detectable in the serum of patients with Crohn’s disease (CD) but display a very poor sensitivity for the disease especially in forms with isolated colonic involvement. In this study we aimed at evaluating performances of these markers in supernatant of cultured colonic biopsies.

Patients with colonic CD (n =  67), ulcerative colitis (UC) (n = 35) and control individuals (n = 37) were prospectively recruited for colonoscopy pinch biopsies and blood sampling. Serum and supernatant of culture tissues were analyzed for ASCA and anti-OmpC. Direct immunofluorescence was also performed on colonic tissues for total IgA detection.

We detected for the first time ASCA IgA/IgG and anti-OmpC IgA in cultured colonic tissue supernatants. For both markers, sensitivities for diagnosing CD were better in supernatants (ASCA: 53.7%, anti-OmpC: 28.4%) than in serum (ASCA: 31.3%, anti-OmpC: 22.4%). Combination of results from a panel of these tests gave the greatest sensitivity ever described for CD diagnosis in colonic forms (70.2%).

In this study, we described, for the first time, ASCA in supernatant of colonic tissue cultures. This assaying approach in CD diagnosis should be taken into consideration in the future especially in CD forms with isolated colonic involvement.

Salmonella Typhi OmpS1 and OmpS2 porins are potent protective immunogens with adjuvant properties

Salmonella enterica serovar Typhi (S. Typhi) is the causal agent of typhoid fever, a disease that primarily affects developing countries. Various antigens from this bacterium have been reported to be targets of the immune response. Recently, the S. Typhi genome has been shown to encode two porins--OmpS1 and OmpS2--which are expressed at low levels under in vitro culture conditions. In this study, we demonstrate that immunizing mice with either OmpS1 or OmpS2 induced production of specific, long-term antibody titres and conferred protection against S. Typhi challenge; in particular, OmpS1 was more immunogenic and conferred greater protective effects than OmpS2. We also found that OmpS1 is a Toll-like receptor 4 (TLR4) agonist, whereas OmpS2 is a TLR2 and TLR4 agonist. Both porins induced the production of tumour necrosis factor and interleukin-6, and OmpS2 was also able to induce interleukin-10 production. Furthermore, OmpS1 induced the over-expression of MHC II molecules in dendritic cells and OmpS2 induced the over-expression of CD40 molecules in macrophages and dendritic cells. Co-immunization of OmpS1 or OmpS2 with ovalbumin (OVA) increased anti-OVA antibody titres, the duration and isotype diversity of the OVA-specific antibody response, and the proliferation of T lymphocytes. These porins also had adjuvant effects on the antibody response when co-immunized with either the Vi capsular antigen from S. Typhi or inactivated 2009 pandemic influenza A(H1N1) virus [A(H1N1)pdm09]. Taken together, the data indicate that OmpS1 and OmpS2, despite being expressed at low levels under in vitro culture conditions, are potent protective immunogens with intrinsic adjuvant properties.

Improved production process for native outer membrane vesicle vaccine against Neisseria meningitidis

An improved detergent-free process has been developed to produce vaccine based on native outer membrane vesicles (NOMV) against Neisseria meningitidis serogroup B. Performance was evaluated with the NonaMen vaccine concept, which provides broad coverage based on nine distinct PorA antigens. Scalable aseptic equipment was implemented, replacing undesirable steps like ultracentrifugation, inactivation with phenol, and the use of preservatives. The resulting process is more consistent and gives a higher yield than published reference processes, enabling NOMV production at commercial scale. Product quality met preliminary specifications for 9 consecutive batches, and an ongoing study confirmed real-time stability up to 12 months after production. As the NOMV had low endotoxic activity and induced high bactericidal titres in mice, they are expected to be safe and effective in humans. The production process is not limited to NonaMen and may be applicable for other N. meningitidis serogroups and other gram-negative pathogens. The current results therefore facilitate the late-stage development and clinical evaluation of NOMV vaccines.

Microbe-host interactions: structure and role of Gram-negative bacterial porins

Gram negative bacteria have evolved many mechanisms of attaching to and invading host epithelial and immune cells. In particular, many outer membrane proteins (OMPs) are involved in this initial interaction between the pathogen and their host. The outer membrane (OM) of Gram-negative bacteria performs the crucial role of providing an extra layer of protection to the organism without compromising the exchange of material required for sustaining life. The OM, therefore, represents a sophisticated macromolecular assembly, whose complexity has yet to be fully elucidated. This review will summarize the structural information available for porins, a class of OMP, and highlight their role in bacterial pathogenesis and their potential as therapeutic targets. The functional role of porins in microbe-host interactions during various bacterial infections has emerged only during the last few decades, and their interaction with a variety of host tissues for adhesion to and invasion of the cell and for evasion of host-defense mechanisms have placed bacterial porins at the forefront of research in bacterial pathogenesis. This review will discuss the role that porins play in activating immunological responses, in inducing signaling pathways and their influence on antibiotic resistance mechanisms that involve modifications of the properties of the OM lipid barrier.

Persistence of hyperinvasive meningococcal strain types during global spread as recorded in the PubMLST database

Neisseria meningitidis is a major cause of septicaemia and meningitis worldwide. Most disease in Europe, the Americas and Australasia is caused by meningococci expressing serogroup B capsules, but no vaccine against this polysaccharide exists. Potential candidates for 'serogroup B substitute' vaccines are outer membrane protein antigens including the typing antigens PorA and FetA. The web-accessible PubMLST database (www.pubmlst.org) was used to investigate the temporal and geographical patterns of associations among PorA and FetA protein variants and lineages defined by combinations of housekeeping genes, known as clonal complexes. The sample contained 3460 isolates with genotypic information from 57 countries over a 74 year period. Although shifting associations among antigen variants and clonal complexes were evident, a subset of strain types associated with several serogroups persisted for decades and proliferated globally. Genetic stability among outer membrane proteins of serogroup A meningococci has been described previously, but here long-lived genetic associations were also observed among meningococci belonging to serogroups B and C. The patterns of variation were consistent with behaviour predicted by models that invoke inter-strain competition mediated by immune selection. There was also substantial geographic and temporal heterogeneity in antigenic repertoires, providing both opportunities and challenges for the design of broad coverage protein-based meningococcal vaccines.

Comparative investigation of the genomic regions involved in antigenic variation of the TprK antigen among treponemal species, subspecies, and strains

Although the three Treponema pallidum subspecies (T. pallidum subsp. pallidum, T. pallidum subsp. pertenue, and T. pallidum subsp. endemicum), Treponema paraluiscuniculi, and the unclassified Fribourg-Blanc treponeme cause clinically distinct diseases, these pathogens are genetically and antigenically highly related and are able to cause persistent infection. Recent evidence suggests that the putative surface-exposed variable antigen TprK plays an important role in both treponemal immune evasion and persistence. tprK heterogeneity is generated by nonreciprocal gene conversion between the tprK expression site and donor sites. Although each of the above-mentioned species and subspecies has a functional tprK antigenic variation system, it is still unclear why the level of expression and the rate at which tprK diversifies during infection can differ significantly among isolates. To identify genomic differences that might affect the generation and expression of TprK variants among these pathogens, we performed comparative sequence analysis of the donor sites, as well as the tprK expression sites, among eight T. pallidum subsp. pallidum isolates (Nichols Gen, Nichols Sea, Chicago, Sea81-4, Dal-1, Street14, UW104, and UW126), three T. pallidum subsp. pertenue isolates (Gauthier, CDC2, and Samoa D), one T. pallidum subsp. endemicum isolate (Iraq B), the unclassified Fribourg-Blanc isolate, and the Cuniculi A strain of T. paraluiscuniculi. Synteny and sequence conservation, as well as deletions and insertions, were found in the regions harboring the donor sites. These data suggest that the tprK recombination system is harbored within dynamic genomic regions and that genomic differences might be an important key to explain discrepancies in generation and expression of tprK variants among these Treponema isolates.

Serum antibodies and anthropometric data at diagnosis in pediatric Crohn's disease

BACKGROUND

Serum antibodies, including ASCA, anti-OmpC, and ANCA, correlate with disease location and predict disease phenotype in inflammatory bowel disease.

AIM

The objective of this study was to determine relationships between serum antibody status and anthropometric data for children with newly diagnosed Crohn's disease.

METHODS

A retrospective review was conducted on children diagnosed with Crohn's disease at our institution from 2003 to 2008. Patients who had ASCA IgA, ASCA IgG, anti-OmpC, and pANCA antibodies, and anthropometric data measured before diagnosis and therapy were included. Z-scores for height and weight were compared among groups according to the presence of specific antibodies. Spearman's rank correlation was used to assess association between antibodies and growth data.

RESULTS

One hundred and two patients, mean age 11.9 years, met the inclusion criteria. Patients with the presence of any of the four antibodies had lower mean height and weight z-scores than patients without any antibodies present. When individual antibodies were studied, patients with positive ASCA titers had lower mean weight and height z-scores than patients without any antibodies present. Spearman's rank correlation coefficient demonstrated a significant association between increasing ASCA titers and lower weight z-scores, but not lower height z-scores.

CONCLUSIONS

Pediatric patients with newly diagnosed Crohn's disease and the presence of ASCA antibodies have lower mean height and weight z-scores. This study provides evidence that specific subsets of children with Crohn's disease may be at greater risk of growth impairment.

The influence of monogalactosyldiacylglycerols from different marine macrophytes on immunogenicity and conformation of protein antigen of tubular immunostimulating complex

The tubular immunostimulating complex (TI-complex) is a novel nanoparticulate antigen delivery system consisting of cholesterol, triterpene glycoside cucumarioside A(2)-2, and glycolipid monogalactosyldiacylglycerol (MGDG) isolated from marine macrophytes. MGDG is crucial for the formation of a lipid matrix for the protein antigen incorporated in TI-complexes. Fatty acid composition and the physical state of this glycolipid depend on the taxonomic position of marine macrophytes. Therefore, the aim of the present work was to study the capacity of MGDGs, isolated from five species of marine macrophytes, to influence conformation and to enhance immunogenicity of porin from Yersinia pseudotuberculosis (YOmpF) as a model antigen of subunit vaccine based on TI-complexes. The trimeric porin was chosen for these experiments, because it was approximately two times more immunogenic than monomeric porin incorporated in TI-complexes. Immunization of mice with YOmpF within TI-complexes, comprised of different MGDGs, revealed a dependence of the immunostimulating effect of TI-complexes on the microvicosity of this glycolipid. TI-complexes comprising MGDGs from Sargassum pallidum and Ulva fenestrata with medium microviscosity induced maximal levels of anti-porin antibodies (four times higher when compared with those induced by pure porin). The adjuvant effect of TI-complexes based on other MGDGs varied by 2.8, 2.3 and 1.3 times for TI-complexes comprised of MGDGs from Zostera marina, Ahnfeltia tobuchiensis, and Laminaria japonica, respectively. MGDGs are also able to influence cytokine mechanisms of immunological regulation. DSC and spectroscopic studies showed that maximal immunostimulating effect of TI-complexes correlated with a moderate stabilizing influence of MGDGs from S. pallidum and U. fenestrata on the conformation of porin. The results obtained suggest lipid "nanofluidics" as a novel strategy for optimizing the immune response to protein antigens within lipid particulate systems.

Escherichia coli K-12 pathogenicity in the pea aphid, Acyrthosiphon pisum, reveals reduced antibacterial defense in aphids

To better understand the molecular basis underlying aphid immune tolerance to beneficial bacteria and immune defense to pathogenic bacteria, we characterized how the pea aphid Acyrthosiphon pisum responds to Escherichia coli K-12 infections. E. coli bacteria, usually cleared in the hemolymph of other insect species, were capable of growing exponentially and killing aphids within a few days. Red fluorescence protein expressing E. coli K-12 laboratory strain multiplied in the aphid hemolymph as well as in the digestive tract, resulting in death of infected aphids. Selected gene deletion mutants of the E. coli K-12 predicted to have reduced virulence during systemic infections showed no difference in either replication or killing rate when compared to the wild type E. coli strain. Of note, however, the XL1-Blue E. coli K-12 strain exhibited a significant lag phase before multiplying and killing aphids. This bacterial strain has recently been shown to be more sensitive to oxidative stress than other E. coli K-12 strains, revealing a potential role for reactive oxygen species-mediated defenses in the otherwise reduced aphid immune system.

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.

[Immunogenic and protective properties of nanosized constructs based on tubular immunostimulating complexes and pore forming protein of Yersinia pseudotuberculosis]

AIM

Evaluation of immunogenic and protective properties of constructs based on subunit porin antigen from Yersinia pseudotuberculosis, immunostimulating complexes (ISCOM) and tubular immunostimulating (TI) complexes.

MATERIALS AND METHODS

Porin antibodies and blood serum cytokines were determined by using EIA. Porin-specific cell immunity was evaluated by DTH reaction inflammation index. Protective activity of porin formulations was determined by measuring specific gravity of animals surviving Yersinia pseudotuberculosis lethal challenge.

RESULTS

Porin in TI complexes develops higher immunogenicity when compared with individual protein or protein with complete Freunds adjuvant. Porin in TI complexes develops higher protective activity, inhibits interferon synthesis in mice. Incorporation of porin into TI complexes results in neutralization of porin suppressive activity against DTH mechanisms and interferon system.

CONCLUSION

TI complexes may be used as perspective carriers for bacterial antigens. TI complexes have adjuvant properties and can provide protective properties to porin vaccine constructs.

High levels of Crohn's disease-associated anti-microbial antibodies are present and independent of colitis in chronic granulomatous disease

Chronic granulomatous disease (CGD) and inflammatory bowel disease (IBD) have overlapping gastrointestinal manifestations. Serum antibodies to intestinal microbial antigens in IBD are thought to reflect a loss of tolerance in the setting of genetically encoded innate immune defects. CGD subjects studied here, with or without colitis, had considerably higher levels of ASCA IgA, ASCA IgG, anti-OmpC, anti-I2, and anti-CBir1, but absent to low pANCA, compared to IBD-predictive cutoffs. Higher antibody levels were not associated with a history of colitis. Except for higher ASCA IgG in subjects <18 years, antibody levels were not age-dependent. In comparison, 7 HIES subjects expressed negative to low antibody levels to all of these antigens; none had colitis. Our results suggest that markedly elevated levels of antimicrobial antibodies in CGD do not correlate with a history of colitis but may reflect a specific defect in innate immunity in the face of chronic antigenic stimulation.

A phase 1 study of a meningococcal native outer membrane vesicle vaccine made from a group B strain with deleted lpxL1 and synX, over-expressed factor H binding protein, two PorAs and stabilized OpcA expression

This phase I clinical trial assessed the safety and immunogenicity of a native outer membrane vesicle (NOMV) vaccine prepared from an lpxL1(-) synX(-) mutant of strain 8570(B:4:P1.19,15:L8-5) of Neisseria meningitidis. Additional mutations enhance the expression of factor H binding protein variant 1 (fHbp v.1), stabilize expression of OpcA and introduce a second PorA (P1.22,14). Thirty-six volunteers were assigned to one of four dose groups (10, 25, 50 and 75 mcg, based on protein content) to receive three intramuscular injections at six week intervals with aluminum hydroxide adjuvant. Specific local and systemic adverse events were solicited by diary and at visits on days 2, 7, and 14 after each vaccination. Blood chemistries, complete blood count, and coagulation studies were measured on each vaccination day and again 2 and 14 days later. Blood for ELISA and serum bactericidal assays was drawn two and six weeks after each vaccination. The proportion of volunteers who developed a fourfold or greater increase in bactericidal activity to the wild type parent of the vaccine strain at two weeks after the third dose was 27 out of 34 (0.79, 95% C.I. 0.65-0.93). Against four other group B strains the response rate ranged from 41% to 82% indicating a good cross reactive antibody response. Depletion assays show contributions to bactericidal activity from antibodies to lipooligosaccharide (LOS), fHbp v.1 and OpcA.

Serological markers for inflammatory bowel disease in AIDS patients with evidence of microbial translocation

BACKGROUND

Breakdown of the gut mucosal barrier during chronic HIV infection allows translocation of bacterial products such as lipopolysaccharides (LPS) from the gut into the circulation. Microbial translocation also occurs in inflammatory bowel disease (IBD). IBD serological markers are useful in the diagnosis of IBD and to differentiate between Crohn's disease (CD) and ulcerative colitis (UC). Here, we evaluate detection of IBD serological markers in HIV-infected patients with advanced disease and their relationship to HIV disease markers.

METHODS

IBD serological markers (ASCA, pANCA, anti-OmpC, and anti-CBir1) were measured by ELISA in plasma from AIDS patients (n = 26) with low CD4 counts (<300 cells/µl) and high plasma LPS levels, and results correlated with clinical data. For meta-analysis, relevant data were abstracted from 20 articles.

RESULTS

IBD serological markers were detected in approximately 65% of AIDS patients with evidence of microbial translocation. An antibody pattern consistent with IBD was detected in 46%; of these, 75% had a CD-like pattern. Meta-analysis of data from 20 published studies on IBD serological markers in CD, UC, and non-IBD control subjects indicated that IBD serological markers are detected more frequently in AIDS patients than in non-IBD disease controls and healthy controls, but less frequently than in CD patients. There was no association between IBD serological markers and HIV disease markers (plasma viral load and CD4 counts) in the study cohort.

CONCLUSIONS

IBD serological markers may provide a non-invasive approach to monitor HIV-related inflammatory gut disease. Further studies to investigate their clinical significance in HIV-infected individuals are warranted.

[Immunochemical characteristics of synthetic peptides incorporating T- and B-cell epitopes nonspecific porins of pathogenic Yersinia]

Multiple antigenic peptides (MAPs), a sequence which include common antigenic epitopes of outer membrane porins (OM) bacteria of the genus Yersinia (Y. pseudotuberculosis, Y. enterocolitica, Y. pestis), pathogenic for humans have been synthesized. After immunization of BALB/c mice the antiserum to the peptide have been obtained. With the help of ELISA we showed that these sera interact with porins isolated from OM pathogenic Yersinia, and MAP interact with antibodies in sera from rabbits immunized with individual porins, and with antibodies in sera of patients with intestinal yersiniosis and pseudotuberculosis.

Identification of outer membrane porin f protein of Yersinia enterocolitica recognized by antithyrotopin receptor antibodies in Graves' disease and determination of its epitope using mass spectrometry and bioinformatics tools

CONTEXT

In addition to genetic susceptibility, Yersinia enterocolitica (YE) infection played an important causative role in the pathogenesis of Graves' disease (GD) through molecular mimicry. However, the specific YE proteins and epitopes recognized by anti-TSH receptor (TSHR) autoantibodies (TRAb) have not been fully clarified, resulting in conflicting results from clinical research.

OBJECTIVE

Our aim was to explore the roles of YE in the pathogenesis of GD and identify the YE proteins and epitopes that are similar to the TSHR and are recognized by TRAb.

DESIGN

Assays of YE antibodies, TRAb, thyroglobulin antibodies, and thyroid microsomal antibodies as well as cross-absorption and two-way immunodiffusion were performed in patients with GD. Using mass spectrometry and the bioinformatics tools of protein structure modeling and epitope prediction, we identified the YE protein and its epitope, which was recognized by TRAb and was similar to TSHR.

RESULTS

Our study demonstrated for the first time that the YE protein outer membrane porin F protein (ompF) shared cross-immunogenicity with a leucine-rich domain of TSHR. The epitope recognized by antihuman TSHR antibody is located within the ompF region of amino acids 190-197, and the polyantibody against ompF protein showed TSAb activity.

CONCLUSIONS

Our results suggest that YE ompF is involved in the production of TRAb and the pathogenesis of GD through molecular mimicry. These findings are potentially important for understanding the role molecular mimicry plays in the disturbance of immune tolerance and the induction of autoimmunity to the TSHR.

[Study of protective properties of recombinant atoxic form of exotoxin A and recombinant outer membrane protein F of Pseudomonas aeruginosa]

AIM

To obtain recombinant atoxic form of Pseudomonas aeruginosa exotoxin A and assess its protective properties during simultaneous administration with recombinant protein F in experiment.

MATERIALS AND METHODS

Genetic methods were employed for construction of deletion variant of P. aeruginosa exotoxin A gene, whereas Escherichia coli cells were used for transformation. Purification of proteins was performed by common method. White outbred mice were used for immunization and experimental infection was produced by intraperitoneal administration of live virulent culture of P. aeruginosa strain PA103.

RESULTS

The gene coding defect form of P. aeruginosa exotoxin A with lacked 106 C-terminal aminoacid residues was cloned. Synthesized protein was nontoxic and immunogenic. Recombinant variants of anatoxin A and outer membrane protein F of P. aeruginosa protected animals from experimental infection caused by toxigenic strain PA103 of P. aeruginosa if were administered separately or concomitantly. Nonetheless, the highest protective effect was observed after immunization with both proteins.

CONCLUSION

Studied recombinant toxoid and OprF could be the candidates for inclusion in vaccines for prevention of pseudomonas infection.

Porin of Shigella dysenteriae directly promotes toll-like receptor 2-mediated CD4+ T cell survival and effector function

Porin of Shigella dysenteriae type 1 up-regulated Toll-like receptor (TLR)2 on CD3-stimulated CD4(+) T cells but could not induce the expression of other TLRs. TLR2 in association with myeloid differentiating factor 88 (MyD88) triggered the downstream signal transduction pathway leading to activation of mitogen-activated protein kinase (MAPK) and nuclear factor kappaB (NF-kappaB), and degradation of IkappaB, the NF-kappaB inhibitor. TLR2 co-stimulation by porin resulted in T cell expansion by inducing both proliferation and survival of the CD4(+) T cells. Extracellular signal-regulated kinase (ERK)1/2 activation inhibitor U0126 and NF-kappaB translocation inhibitor SN-50 significantly inhibited proliferation of T cells, highlighting a direct role of ERK and NF-kappaB in the process. However, cell survival involving Bcl-X(L) induction was found to be regulated essentially by ERK with no significant role of NF-kappaB. Porin-induced proliferation was supported by induction of IL-2 and CD25 that are known to play a pivotal role in T cell expansion. Apart from inducing T cell proliferation, porin triggered effector functions of the cells, evident from TLR2- and MyD88-dependent release of type 1 cytokines tumor necrosis factor (TNF) and interferon (IFN)-gamma along with the induction of type 1 chemokines macrophage-inflammatory protein (MIP)-1alpha and MIP-1beta and their receptor CCR5. The proliferation, survival and effector function of CD4(+) T cells through TLR2 co-stimulation show the capability of porin to directly turn adaptive immunity into action.

The porin OmpD from nontyphoidal Salmonella is a key target for a protective B1b cell antibody response

Invasive nontyphoidal Salmonella (NTS), including Salmonella typhimurium (STm), are major yet poorly-recognized killers of infants in sub-Saharan Africa. Death in these children is usually associated with bacteremia, commonly in the absence of gastrointestinal symptoms. Evidence from humans and animal studies suggest that severe infection and bacteremia occur when specific Ab is lacking. Understanding how Ab responses to Salmonella are regulated will help develop vaccines against these devastating infections. STm induces atypical Ab responses characterized by prominent, accelerated, extrafollicular T-independent (TI) Ab against a range of surface antigens. These responses develop without concomitant germinal centers, which only appear as infection resolves. Here, we show STm rapidly induces a population of TI B220(+)CD5(-) B1b cells during infection and TI Ab from B1b cells targets the outer membrane protein (Omp) porins OmpC, OmpD and OmpF but not flagellin. When porins are used as immunogens they can ablate bacteremia and provide equivalent protection against STm as killed bacterial vaccine and this is wholly B cell-dependent. Furthermore Ab from porin-immunized chimeras, that have B1b cells, is sufficient to impair infection. Infecting with porin-deficient bacteria identifies OmpD, a protein absent from Salmonella Typhi, as a key target of Ab in these infections. This work broadens the recognized repertoire of TI protein antigens and highlights the importance of Ab from different B cell subsets in controlling STm infection. OmpD is a strong candidate vaccine target and may, in part, explain the lack of cross-protection between Salmonella Typhi and STm infections.

IBD-associated TL1A gene (TNFSF15) haplotypes determine increased expression of TL1A protein

Background

The recently identified member of the TNF superfamily TL1A (TNFSF15) increases IFN-γ production by T cells in peripheral and mucosal CCR9+ T cells. TL1A and its receptor DR3 are up-regulated during chronic intestinal inflammation in ulcerative colitis and Crohn's disease (CD). TL1A gene haplotypes increase CD susceptibility in Japanese, European, and US cohorts.

Methodology and Principal Findings

Here we report that the presence of TL1A gene haplotype B increases risk in Jewish CD patients with antibody titers for the E. coli outer membrane porin C (OmpC+) (Haplotype B frequency in Jewish CD patients: 24.9% for OmpC negative and 41.9% for OmpC positive patients, respectively, P≤0.001). CD14+ monocytes isolated from Jewish OmpC+ patients homozygous for TL1A gene haplotype B express higher levels of TL1A in response to FcγR stimulation, a known inducing pathway of TL1A, as measured by ELISA. Furthermore, the membrane expression of TL1A is increased on peripheral monocytes from Jewish but not non-Jewish CD patients with the risk haplotype.

Conclusions and Significance

These findings suggest that TL1A gene variation exacerbates induction of TL1A in response to FcγR stimulation in Jewish CD patients and this may lead to chronic intestinal inflammation via overwhelming T cell responses. Thus, TL1A may provide an important target for therapeutic intervention in this subgroup of IBD patients.

[Immunogenicity of multi-epitopes gene of major outer membrane protein of Chlamydia trachomatis]

OBJECTIVE

To construct a recombinant eukaryotic expression plasmid pcDNA3.1-Ct MOMP168 including Ct MOMP multi-epitopes gene, and evaluate the Ct MOMP-specific humoral and cellular immune response induced by pcDNA3.1-Ct MOMP168 in BALB/c mice.

METHODS

Recombinant plasmid pcDNA3.1-Ct MOMP168 including Ct MOMP multi-epitopes gene was constructed. Then, BALB/c mice were randomly assigned to receive (intramuscular injection) either pcDNA3.1-Ct MOMP168 or pcDNA3.1 or PBS (n = 12, 100 microg/time per mouse), and the same immunization schedule was repeated for the third time at 2 week intervals. The titers of anti-Ct MOMP antibody and its antibody subtypes in sera, the cytotoxicity of Ct MOMP-specific cytotoxic T lymphocyte (CTL) in spleen, and the level of cytokine (IFN-gamma, IL-4, IL-10)-producing CD3(+) T cells in spleen were detected by ELISA, LDH release assays and intracellular cytokine staining-fluorescence activated cell sorter (ICS-FACS), respectively.

RESULTS

The recombinant plasmid pcDNA3.1-Ct MOMP168 was able to induce Ct-specific antibody response (A(490) = 0.973 +/- 0.136; serum titer was 1:1000) as compared with pcDNA3.1 (A(490) = 0.180 +/- 0.025) and PBS (A(490) = 0.110 +/- 0.015), and the major antibody subtype was IgG2a with statistical significance (F = 106.884, P < 0.05). When the ratio of effector cells and target cells reached to 50:1, the activity of cytotoxic T-lymphocyte in pcDNA3.1-Ct MOMP168 immunized mice (41.71% +/- 8.34%) was significantly higher (F = 22.315, P < 0.05) than that in pcDNA3.1 immunized mice (18.40% +/- 3.45%) and PBS immunized mice (14.50% +/- 2.42%). The levels of CD3(+) IFN-gamma(+) T cells in pcDNA3.1-Ct MOMP168 immunized mice (1.15% +/- 0.16%) were significantly higher (F = 99.638, P < 0.05) than that in pcDNA3.1 immunized mice (0.12% +/- 0.08%) and PBS immunized mice (0.09% +/- 0.03%), while the significant difference in the levels of IL-4(+) CD3(+) T cells and IL-10(+) CD3(+) T cells was not observed (F = 0.886 and 1.112, P > 0.05) between pcDNA3.1-Ct MOMP168 immunized mice (0.13% +/- 0.08% and 0.14% +/- 0.08%) and pcDNA3.1 (0.07% +/- 0.05% and 0.13% +/- 0.06%) or PBS immunized mice (0.08% +/- 0.04% and 0.07% +/- 0.04%).

CONCLUSION

In BALB/c mice, the recombinant plasmid pcDNA3.1-Ct MOMP168 might induce not only the generation of Ct-specific antibody, but also the high level of Ct MOMP-specific CD3(+) IFN-gamma(+) T cells.