Immune Responses during Human Schistosomiasis mansoni

We present a method for the examination of antiidiotypic cellmediated reactivity during chronic human infections. Pooled and individual sera from patients with schistosomiasis. mansoni were purified on immunoaffinity columns of schistosomal egg antigens (SEA). The eluates contained anti-SEA antibodies, but not SEA. These antibody preparations, and their F(ab')2 fragments, stimulated dose-dependent proliferation of peripheral blood mononuclear cells (PBMN) and T lymphocytes from some, but not all active or former schistosomiasis mansoni patients, and could do so autologously. Stimulation required presentation by plasticadherent cells. The eluates did not stimulate PBMN from persons who had never had schistosomiasis. Affinity-purified anti-SEA antibodies from former patients (cured for >10 yr) did not stimulate PBMN from patients with active infections. Reabsorption on SEA columns removed stimulatory activity from the eluates. We propose that multiclonal, SEA-related idiotypes expressed by some anti-SEA antibodies stimulate proliferation of T lymphocytes that express antiidiotypic specificities.