Antigenicity of Trichomonas vaginalis heat-shock proteins in human infections

Patients infected with Trichomonas vaginalis mount humoral and cellular imm une responses that often do not protect against reinfection. The oxidative stressors produced by leukocytes may trigger a heat-shock-like response in T. vaginalis trophozoites, helping the parasite to survive host immune defe nses. The antigenicity of T. vaginalis heat-shock proteins (HSPs) was exami ned by immunoprecipitation of T. vaginalis heat-induced proteins with sera from infected patients and controls. When T. vaginalis was heat-shocked, HS Ps of 169-167 and 140-137 kDa were specifically recognized by sera from inf ected male and female patients. However, the majority of T. vaginalis HSPs were also immunoprecipitated by control sera; all sera recognized 72- to 71 -kDa, 47- to 45-kDa, 38- to 37-kDa, 35-kDa, and 31-kDa heat-induced protein s. At least 15 proteins from non-heat-shocked T. vaginalis were immunopreci pitated by sera from infected patients and controls, indicating that natura l or cross-reacting antibodies could participate in host responses to trich omoniasis. Molecules of 158, 135, 89, and 74-72 kDa were immunoprecipitated from some non-heat-shocked parasites only by patients' sera. A 38-kDa T. v aginalis protein was immunoprecipitated only by sera from infected females and may be specific for infection in women.