Evidence of genetic susceptibility to Chlamydia trachomatis-induced pelvic inflammatory disease in the pig-tailed macaque

HLA-DR and HLA-DQ Polymorphism Correlation with Sexually Transmitted Infection Caused by Chlamydia trachomatis

Background and Objectives: Chlamydia trachomatis (C. trachomatis) represents one of the most prevalent bacterial sexually transmitted diseases. This study aims to explore the relationship between HLA alleles/genotypes/haplotypes and C. trachomatis infection to better understand high-risk individuals and potential complications. Materials and Methods: This prospective study recruited participants from Transylvania, Romania. Patients with positive NAAT tests for C. trachomatis from cervical/urethral secretion or urine were compared with controls regarding HLA-DR and -DQ alleles. DNA extraction for HLA typing was performed using venous blood samples. Results: Our analysis revealed that the presence of the DRB1*13 allele significantly heightened the likelihood of C. trachomatis infection (p = 0.017). Additionally, we observed that individuals carrying the DRB1*01/DRB1*13 and DQB1*03/DQB1*06 genotype had increased odds of C. trachomatis infection. Upon adjustment, the association between the DRB1*01/DRB1*13 genotype and C. trachomatis remained statistically significant. Conclusions: Our findings underscore the importance of specific HLA alleles and genotypes in influencing susceptibility to C. trachomatis infection. These results highlight the intricate relationship between host genetics and disease susceptibility, offering valuable insights for targeted prevention efforts and personalized healthcare strategies.

Chlamydia trachomatis and the HLA involvement in the development of infection and disease: a narrative review

Introduction

CT (Chlamydia trachomatis) is among the most common pathogens leading to sexually transmitted diseases. Considering the uncertain mechanism by which HLA polymorphisms influence the CT infection, reinfection, comorbidities or evolution and because there is no consensus regarding the alleles involved in the pathogenesis of the infection, we considered necessary to perform a review to summarize the current knowledge of HLA related to CT.

Methods

Pubmed was researched using key terms. Out of the 198 results found, we analyzed articles of all types which describe how the MHC, through HLA alleles, participates in the different stages of CT penetration in the body, including studies about cells or other molecules involved in the process.

Results

Almost 40% of the variation in the clinical course of CT infection depends on host genetic factors. There are haplotypes that influence the infection susceptibility/resistance, haplotypes that are involved in the recurrence of the infection, haplotypes that are related to tubal infertility, pelvic inflammatory disease development or trachoma. Antibody to Chsp60 (influenced by MHC genes) has been observed to correlate with late tissue-damaging sequelae. Toll-like receptors were found to increase the susceptibility to CT. The association of HLA-B27 creates susceptibility of reactive arthritis in the organisms infected by CT, but does not influence the carriage of CT.

Conclusion

We identified HLA haplotypes belonging both to MHC class l and ll, which influence different stages of CT infection. Genetic risk factors still need research, especially on Caucasians. Studies are moving towards designing a safe and effective vaccine.

Comparable Genital Tract Infection, Pathology, and Immunity in Rhesus Macaques Inoculated with Wild-Type or Plasmid-Deficient Chlamydia trachomatis Serovar D

Rhesus macaques were studied to directly address the potential for plasmid-deficient Chlamydia trachomatis to serve as a live attenuated vaccine in the genital tract. Five repeated cervical inoculations of rhesus macaques with wild-type serovar D strain D/UW-3/Cx or a plasmid-deficient derivative of this strain, CTD153, resulted in infections with similar kinetics and induced comparable levels of protective immunity. After all animals received five challenges with D/UW-3/Cx, levels of inflammation observed grossly and histologically were similar between the groups. Animals in both groups developed evidence of oviduct dilatation; however, reduced oviduct dilatation was observed for "controllers," i.e., animals without detectable chlamydial DNA in the fimbriae at weeks 5 and 12. Grouping animals into "ascenders" and "controllers" revealed that elevated early T cell responses were associated with protection, whereas higher antibody responses were associated with ascension. Protected animals shared common major histocompatibility complex (MHC) alleles. Overall, genetic differences of individual animals, rather than the presence or absence of the chlamydial plasmid in the primary infecting strain, appeared to play a role in determining the outcome of infection.

Development of a pigtail macaque model of sexually transmitted infection/HIV coinfection using Chlamydia trachomatis, Trichomonas vaginalis, and SHIV(SF162P3)

BACKGROUND

Sexually transmitted infections (STIs) are associated with an increased risk of HIV infection. To model the interaction between STIs and HIV infection, we evaluated the capacity of the pigtail macaque model to sustain triple infection with Trichomonas vaginalis, Chlamydia trachomatis, and SHIV(SF162P3).

METHODS

Seven SHIV(SF162P3) -infected pigtail macaques were inoculated with T. vaginalis only (n = 2), C. trachomatis only (n = 1), both T. vaginalis and C. trachomatis (n = 2), or control media (no STI; n = 2). Infections were confirmed by culture and/or nucleic acid testing. Genital mucosa was visualized by colposcopy.

RESULTS

Characteristic gynecologic signs were observed for both STIs, but not in control animals. Manifestations were most prominent at days 7-10 post-infection. STIs persisted between 4 and 6 weeks and were cleared with antibiotics.

CONCLUSIONS

These pilot studies demonstrate the first successful STI-SHIV triple infection of pigtail macaques, with clinical presentation of genital STI symptoms similar to those observed in humans.

Immunogenicity of a vaccine formulated with the Chlamydia trachomatis serovar F, native major outer membrane protein in a nonhuman primate model

To determine the ability of a vaccine formulated with the genital Chlamydia trachomatis, serovar F, native major outer membrane protein (Ct-F-nMOMP), to induce systemic and mucosal immune responses, rhesus macaques (Macaca mulatta) were immunized three times by the intramuscular (i.m.) and subcutaneous (s.c.) routes using CpG-2395 and Montanide ISA 720 VG, as adjuvants. As controls, another group of M. mulatta was immunized with ovalbumin instead of Ct-F-nMOMP using the same formulation and routes. High levels of Chlamydia-specific IgG and IgA antibodies were detected in plasma, vaginal washes, tears, saliva, and stools from the Ct-F-nMOMP immunized animals. Also, high neutralizing antibody titers were detected in the plasma from these animals. Monkeys immunized with ovalbumin had no detectable Chlamydia-specific antibodies. Furthermore, as measured by a lymphoproliferative assay, significant Chlamydia-specific cell-mediated immune responses were detected in the peripheral blood mononuclear cells (PBMC) from the rhesus macaques vaccinated with Ct-F-nMOMP when compared with the animals immunized with ovalbumin. In addition, the levels of two Th1 cytokines, IFN-γ and TNF-α, were significantly higher in the animals immunized with Ct-F-nMOMP when compared with those from the monkeys immunized with ovalbumin. To our knowledge, this is the first time that mucosal and systemic immune responses have been investigated in a nonhuman primate model using a subunit vaccine from a human genital C. trachomatis serovar.

Chlamydia trachomatis infection: host immune responses and potential vaccines

Chlamydia trachomatis causes genital tract infections that affect men, women, and children on a global scale. This review focuses on innate and adaptive immune responses in the female reproductive tract (FRT) to genital tract infections with C. trachomatis. It covers C. trachomatis infections and highlights our current knowledge of genital tract infections, serovar distribution, infectious load, and clinical manifestations of these infections in women. The unique features of the immune system of the FRT will be discussed and will include a review of our current knowledge of innate and adaptive immunity to chlamydial infections at this mucosal site. The use of animal models to study the pathogenesis of, and immunity to, Chlamydia infection of the female genital tract will also be discussed and a review of recent immunization and challenge experiments in the murine model of chlamydial FRT infection will be presented.

Identification of an iron-responsive protein that is antigenic in patients with Chlamydia trachomatis genital infections

Chlamydia trachomatis is an important cause of immune-mediated damage to the reproductive tract of infected patients. Certain chlamydial antigens and host genetic factors have been identified as contributing to immunopathological events, but a comprehensive understanding of specific components involved in destructive vs. protective immune responses to chlamydial infections is far from clear. In this study, it is shown that C. trachomatis-infected patients generate antibodies against an iron-responsive chlamydial protein, YtgA. The identity of YtgA was confirmed by mass spectrometry following two-dimensional polyacrylamide gel electrophoresis and Western blot analysis. This finding underscores a necessity to examine patient sera samples to identify chlamydial antigens that are likely encountered and important to the immune response during human infections.

Tubal Pathology: The Role of Hormonal Contraception, Intrauterine Device Use and Chlamydia trachomatis Infection

BACKGROUND

The aim of the present study was to identify a possible association between tubal pathology and the contraceptive methods previously used, especially third generation copper intrauterine devices (IUDs).

METHOD

In this retrospective unmatched case-control study, use of contraceptive methods and Chlamydia trachomatis antibody titres were compared in women with tubal occlusion (n = 84) and infertile women with tubal patency (n = 253) demonstrated by hysterosalpingography. Contraceptive methods were also compared to primiparous women with natural pregnancy.

RESULTS

A significantly higher percentage of women with tubal occlusion had previously used an IUD. Positive C. trachomatis antibody testing was found significantly more often in women with tubal occlusion. Neither hormonal contraceptives nor condoms were associated with an increased risk for uni- or bilateral tubal occlusion.

CONCLUSION

In the present study, we observed an increased rate of tubal occlusions in previous IUD users. This should be considered in the contraceptive counseling of young and nulliparous women.

Heat shock protein 60 is the major antigen which stimulates delayed-type hypersensitivity reaction in the macaque model of Chlamydia trachomatis salpingitis

Chlamydial delayed-type hypersensitivity antigens were analyzed by using the subcutaneous salpingeal autotransplant model of Macaca nemestrina infected with Chlamydia trachomatis serovar E. Heat shock protein 60 was the only antigen shown to induce delayed-type hypersensitivity among other antigens tested, including UV-inactivated organisms, recombinant major outer membrane protein, purified outer membrane proteins, and heat shock protein 10.

Pathogenesis of Chlamydia induced pelvic inflammatory disease

Further research is necessary to elucidate the pathogenesis of chlamydial PID. It is hoped that these endeavours will eventually lead to a vaccine to prevent not only chlamydia infection, but also chlamydia associated infertility, ectopic pregnancy, and chronic pelvic pain. In the meantime we need to develop strategies to prevent primary and secondary chlamydia infection and its sequelae. Recently, Scholes et. al demonstrated that a population based approach to identify and test women at high risk for cervical C trachomatis infection effectively reduced risk of PID. Hopefully, through the use of public health measures, we can see similar decreases of chlamydia associated genital tract disease worldwide.

Vaccines against Chlamydia: approaches and progress

Infections of the eye and genital tract with the bacterium Chlamydia trachomatis are a major cause of morbidity worldwide and are costly to treat. Development of a vaccine capable of protecting against infection or severe disease presents special challenges but would be the most effective long-term option for control of chlamydial disease. Progress has been made in understanding protective and pathological immune mechanisms in these infections, and a number of potential vaccine candidates have been developed.