Subjects recovering from human ocular chlamydial infection have enhanced lymphoproliferative responses to chlamydial antigens compared with those of persistently diseased controls.

Cell-mediated immune responses to chlamydial and common recall antigens were measured in 26 subjects whose clinical signs of trachoma persisted over 6 months of follow-up and in 21 subjects whose clinical signs resolved spontaneously over the same period. Seven-day lymphocyte proliferative responses to chlamydial but not common recall antigens were significantly greater in subjects whose disease resolved spontaneously. There was, however, no detectable difference between the two groups in gamma interferon levels in supernatants from lymphocyte cultures stimulated with these antigens. These results are consistent with the hypothesis that cell-mediated immune responses play an important role in the clearance of ocular chlamydial infection in humans.