Immune mechanisms in chlamydial eye infection: cellular immune responses in chronic and acute disease.

The current studies detail cell-mediated immune responses to Chlamydia trachomatis antigen in both acute and chronically infected monkeys. Peripheral blood mononuclear leukocytes (PBMLs) from three groups of animals (immunized before infection, not immunized before infection, and chronically infected) were tested for the capacity to proliferate in response to C. trachomatis antigen in vitro. Only those animals that had been systemically immunized before acute ocular infection responded significantly. Coculturing macrophages from nonresponding animals with T cells from D-histocompatible responding animals showed that the ability to present antigen was unaffected in nonresponding animals. These studies also demonstrated that removal of suppressor T cells from PBMLs before culture resulted in increased proliferation in the chronically infected group and suggested that the nonresponsiveness seen in chronic ocular disease may be mediated by suppressor T cells.