Demonstration of Delayed Hypersensitivity in Chlamydia trachomatis Salpingitis in Monkeys: A Pathogenic Mechanism of Tubal Damage

The role of delayed hypersensitivity in the pathogenesis of Chlamydia trachomatis salpingitis was studied in the monkey “pocket” model. Pigtailed monkeys (Macaca nemestrina) were sensitized by inoculation of live C. trachomatis organisms (E/UW-5lex) into subcutaneous pockets containing salpingeal autotransplants. At 21 days, affinity-purified recombinant C. trachomatis heat-shock protein (rhsp60) wasinjected into pockets either previouslysensitizedwith C. trachomatis or not sensitized in the same monkey. Delayed-type hypersensitivity reaction was observed, characterized bymononuclear cell infiltration with peak reaction at 48 h. Injection of rhsp60 into the pockets of a naive animal did not induce inflammation. This study showed that C. trachomatis infection in monkeys induced delayed hypersensitivity, which is mediated by hsp60. Histologic findings of the salpinx were consistent with delayed hypersensitivity reaction observed in ocular C. trachomatis infection, further suggesting a similar pathogenesis for both salpingitis and trachoma.