Long-term effect of prenatal exposure to maternal microfilaraemia on immune responsiveness to filarial parasite antigens.

To identify long-term effects of prenatal exposure to maternal filarial-parasite infection, we assessed lymphocyte responses in 21 Polynesian children born 17-19 years previously to mothers diagnosed as being microfilaraemic or infection-free. All children lived on an island endemic for bancroftian filariasis but were free from infection at the time of study. While children (n = 10) of infection-free mothers responded vigorously to microfilarial antigen with lymphocyte proliferation, production of interleukin 2 (IL-2), IL-5, IL-10, granulocyte macrophage colony-stimulating factor (GM-CSF), and interferon gamma (IFN-gamma), cellular hyporesponsiveness was seen in children (n = 11) born to microfilaraemic mothers. The hyporesponsiveness appeared restricted to microfilarial antigens and did not extend to non-parasite antigens. These findings suggest that hyporesponsiveness resulted from in-utero acquisition of tolerance to microfilarial antigens in chronically-infected mothers.