Genital Chlamydia trachomatis: Understanding the Roles of Innate and Adaptive Immunity in Vaccine Research

Abstract

SUMMARY Chlamydia trachomatis is the leading cause of bacterial sexually transmitted disease worldwide, and despite significant advances in chlamydial research, a prophylactic vaccine has yet to be developed. This Gram-negative obligate intracellular bacterium, which often causes asymptomatic infection, may cause pelvic inflammatory disease (PID), ectopic pregnancies, scarring of the fallopian tubes, miscarriage, and infertility when left untreated. In the genital tract, Chlamydia trachomatis infects primarily epithelial cells and requires Th1 immunity for optimal clearance. This review first focuses on the immune cells important in a chlamydial infection. Second, we summarize the research and challenges associated with developing a chlamydial vaccine that elicits a protective Th1-mediated immune response without inducing adverse immunopathologies.

Chlamydial polymorphic membrane proteins: regulation, function and potential vaccine candidates

“…11 The first chlamydial vaccine studies utilized avirulent intact live C. trachomatis as a prophylactic for trachoma infection. However, even though in some cases the vaccine provided considerable protection from infection and pathology, some vaccinated individuals developed more severe disease after subsequent C. trachomatis infection.…”

“…[4][5][6][7][8][9][10][11] C. trachomatis is of particular importance to human health because the infection is mostly asymptomatic and induces inflammatory responses that can lead to immunopathological sequelae. The World Health Organization estimates that since 2008 there are over 100 million new sexually transmitted cases due to C. trachomatis infection.…”

Chlamydia trachomatis: the Persistent Pathogen

“…Following its invasion of the host cell cytoplasm, PAMPs on the newly incorporated EB are also recognized by the cytoplasmic pattern recognition receptor, nucleotide-binding oligomerization domain protein 1 (NOD1), resulting in additional proinflammatory gene activation (19). The phagocytosis of C. trachomatis and the subsequent expression of discrete antigens on the cell surface lead to T and B lymphocyte activation and the generation of chlamydial antigen-specific cell-mediated and humoral immunity (20). In a proportion of infected women, some organisms migrate to the uterus and fallopian tubes, where they utilize their unique characteristics to initiate a chronic infection.…”

Transcriptional Profiling of Human Epithelial Cells Infected with Plasmid-Bearing and Plasmid-Deficient Chlamydia trachomatis

“…Chlamydial infections of the urogenital mucosae are the most common bacterial cause of sexually transmitted diseases in both industrialized nations and developing countries (3,4). Chlamydial infection of the female genital tract can result in serious sequelae, such as salpingitis, tubal factor infertility, and ectopic pregnancy (5).…”