The influence of local antichlamydial antibody on the acquisition and persistence of human ocular chlamydial infection: IgG antibodies are not protective

Abstract

SUMMARYIn order to study the effect of antichlamydial antibodies in ocular secretions on resistance to ocular chlamydial infection and clearance of this infection, we have performed linked longitudinal studies in a Gambian village in which trachoma is endemic. We have measured IgG and IgA antibody levels to a local serotype B isolate of Chlamydia trachomatis by amplified enzyme immunoassay, and chlamydial antigen levels in conjunctival swabs using a commercially available immunoassav which detects chlamydial glycolipid. Having previously demonstrated that sharing a bedroom with a case of active trachoma is a risk factor for acquisition of the disease, we have analysed the effect of IgG and IgA antibody on the acquisition and persistance of clinical trachoma after controlling for age, sex, exposure to infection and for the presence of chlamydial antigen using a Poisson regression model. We have found that the presence of antichlamydial IgG in ocular secretions of disease-free subjects is associated with an increased incidence of trachoma. IgA antibody shows an opposite trend, but this is not statistically significant. One possible explanation of these findings is that antichlamydial IgG antibodies enhance the infectivity of C. trachomatis for the human eye; this could have major implications for the development of a chlamydial vaccine.

The Natural History of Trachoma Infection and Disease in a Gambian Cohort with Frequent Follow-Up

“…This is in agreement with an earlier follow-up study in the same population [30]. This may be the result of low statistical power or the potential importance of other epitopes and immune mechanisms in protection against infection and disease resolution [44].…”

Towards a safe and effective chlamydial vaccine: Lessons from the eye

“…Indeed, the presence of anti-chlamydial IgG in ocular secretions was associated with an increased incidence of active trachoma in this study. The incidence was lower in subjects with anti-chlamydia IgA antibodies in ocular secretions, but the difference was not statistically significant [42]. In NHPs reduction in shedding and clearance of Ct infection was associated with antibody responses to a limited number of native proteins (MOMP, PmpD, Hsp60, CPAF, pgp3 and 3 as yet unidentified polypeptides) which were slowly acquired as the B cell immune response matured [43].…”

Active Trachoma Is Associated with Increased Conjunctival Expression ofIL17Aand Profibrotic Cytokines

“…Immunopathological correlates of active trachoma have been investigated using a number of different approaches, including peripheral blood mononuclear cell (PBMC) responses to chlamydial antigens (4), tear immunoglobulin and cytokine detection (5,19,48), conjunctival gene expression analysis by reverse transcription-PCR (RT-PCR) (6,7), and, more recently, whole-conjunctival-transcriptome analysis (35). From this body of work, some broad conclusions emerge.…”