Male genital tract immune response against Chlamydia trachomatis infection

Abstract

Chlamydia trachomatis is the most commonly reported agent of sexually transmitted bacterial infections worldwide. This pathogenfrequently leads to persistent, long-term, subclinical infections, which in turn may cause severe pathology in susceptible hosts. This isin part due to the strategies that Chlamydia trachomatis uses to survive within epithelial cells and to evade the host immune response,such as subverting intracellular trafficking, interfering signaling pathways and preventing apoptosis. Innate immune receptors such astoll-like receptors expressed on epithelial and immune cells in the genital tract mediate the recognition of chlamydial molecularpatterns. After bacterial recognition, a subset of pro-inflammatory cytokines and chemokines are continuously released by epithelialcells. The innate immune response is followed by the initiation of the adaptive response against Chlamydia trachomatis, which in turnmay result in T helper 1-mediated protection or in T helper 2-mediated immunopathology. Understanding the molecular mechanismsdeveloped by Chlamydia trachomatis to avoid killing and host immune response would be crucial for designing new therapeuticapproaches and developing protective vaccines. In this review, we focus on chlamydial survival strategies and the elicited immuneresponses in male genital tract infections.