LONG-TERM EFFECT OF PRENATAL EXPOSURE TO MATERNAL MICROFILAREMIA ON IMMUNE RESPONSIVENESS TO FILARIAL PARASITE ANTIGENS

To identify long-term effects of prenatal exposure to maternal filaria l-parasite infection, we assessed lymphocyte responses in 21 Polynesia n children born 17-19 years previously to mothers diagnosed as being m icrofilaraemic or infection-free. All children lived on an island ende mic for bancroftian filariasis but were free from infection at the ti me of study. While children (n = 10) of infection-free mothers respond ed vigorously to microfilarial antigen with lymphocyte proliferation, production of interleukin 2 (IL-2), IL-5, IL-10, granulocyte macrophag e colony-stimulating factor (GM-CSF), and interferon gamma (IFN-gamma) , cellular hyporesponsiveness was seen in children (n = 11) born to mi crofilaraemic mothers. The hyporesponsiveness appeared restricted to m icrofilarial antigens and did not extend to non-parasite antigens. The se findings suggest that hyporesponsiveness resulted from in-utero acq uisition of tolerance to microfilarial antigens in chronically-infecte d mothers.