Immunopathogenesis of Chlamydial Infections

Abstract

Chlamydial infections lead to a number of clinically relevant diseases and induce significant morbidity in human populations. It is generally understood that certain components of the host immune response to infection also mediate such disease pathologies. A clear understanding of pathogenic mechanisms will enable us to devise better preventive and/or intervention strategies to mitigate the morbidity caused by these infections. Over the years, numerous studies have been conducted to explore the immunopathogenic mechanisms of Chlamydia-induced diseases of the eye, reproductive tract, respiratory tract, and cardiovascular systems. In this article, we provide an overview of the diseases caused by Chlamydia, animal models used to study disease pathology, and a historical context to the efforts to understand chlamydial pathogenesis. Furthermore, we discuss recent findings regarding pathogenesis, with an emphasis on the role of the adaptive immune response in the development of chlamydial disease sequelae. Finally, we summarize the key insights obtained from studies of chlamydial pathogenesis and avenues that remain to be explored in order to inform the next steps of vaccine development against chlamydial infections.

Rectal administration of a chlamydial subunit vaccine protects against genital infection and upper reproductive tract pathology in mice

“…trachomatis [ 51 ]. Studies in animal models also suggest CD8 T cells and other immune mechanisms play a major role in Chlamydia -induced upper tract pathology, including infertility [ 47 , 52 ].…”

Intranasal immunization with recombinant chlamydial protease‐like activity factor attenuates atherosclerotic pathology following Chlamydia pneumoniae infection in mice

“…However, these disease sequelae were not induced by C. trachomatis infection in mice or guinea pigs and therefore we have not been able to confirm the efficacy of the vaccine against the human pathogen. In this context, we noted that CPAF is a highly conserved chlamydial protein, and a strong association between C. pneumoniae and exacerbation of atherosclerosis in human individuals, and a cause-and-effect relationship in mice and rabbits has been demonstrated 1 . We have now demonstrated that rCPAF±IL-12 vaccination significantly attenuates C. pneumoniae -induced exacerbation of atherosclerosis in the C57BL/6 male mouse model.…”

Koala immunogenetics and chlamydial strain type are more directly involved in chlamydial disease progression in koalas from two south east Queensland koala populations than koala retrovirus subtypes

“…High c-hsp60 antibody titres in koalas have been associated with fibrous occlusion of the uterus or uterine tube, however their role in chlamydial pathogenesis in koalas remains unclear as they were also associated with lower levels of active inflammation and fewer chlamydial inclusions 28 . Human studies suggest that although the Class II MHC defined anti-chlamydial antibody response appears to be important for chlamydial clearance and c-hsp60 antibodies are protective, it does not always prevent pathology 29,30 .…”