Immune responses during human schistosomiasis mansoni. I. In vitro lymphocyte blastogenic responses to heterogeneous antigenic preparations from schistosome eggs, worms and cercariae.

In vitro lymphocyte blastogenesis assays were performed using peripheral blood lymphocytes obtained from patients with schistosomiasis mansoni. Their infection was well characterized both clinically and in regard to the duration and intensity of Schistosoma mansoni infection. Subjects who were either not infected with any helminths or who were negative for S. mansoni but infected with other helminths provided two control groups. Cultures were exposed to various concentrations of heterogeneous soluble antigens prepared either from S. mansoni eggs, worms, or cercariae. In this series there was no statistical correlation between the intensity of infection (as determined by eggs/ml of feces) and the degree of cell-mediated reactivity observed by lymphocyte blastogenesis to any of the antigenic preparations. Individual patient lymphocyte responsiveness varied considerably. However, analysis of the data by groups, based upon the longevity of their S. mansoni infection, demonstrated different patterns of reactivity in regard to the antigen preparations. Responses to the egg antigens were only present early in infection. In contrast, reactivities stimulated by either the worm or cercarial preparations increased in a direct relationship to the duration of S. mansoni infection.