The purpose of this project is to delineate the mechanisms involved in regulating the humoral and cellular responses in patients with filariasis and other disease states. Immunoregulatory studies have examined the phenomenon of antigen-specific anergy in microfilaremic patients by showing this anergy to be a result of a diminished frequency of proliferating cells to parasite antigen. In vitro models of parasite-antigen driven antibody production along with recombinant lymphokines and neutralizing antibodies have been used to understand the signals necessary to regulate antibody production in response to parasite antigen at a molecular level.