Evaluation of Immune Responders in Human Schistosomiasis

Cellular immune responses to Schistosoma mansoni recombinant and native antigens were investigated in a defined study population of 64 individuals in Egypt, where data collected from a 2-year observation of exposure, infection and reinfection pattern were used to categorically classify putative resistant (R) and susceptible (S) individuals. Using peripheral blood mononuclear cells (PBMCs) of individuals enrolled in the study, in vitro lymphocyte proliferation and cytokine (IL-5, IL-10 and IFN-γ) production in response to defined recombinant and native paramyosin antigens ("R-Para" and "N-Para", respectively) and native soluble adult worm antigen preparation (SAWA) were measured. In addition, cellular responses to the "R-Para" and "SAWA" antigens suggest that the Th1 type of response appears to be important in predicting resistance in this population. Of the recombinant Ag tested, R-Para induced significant levels of IFN-γ. The production of IL-10, a Th2-type cytokine was strongly implicated in immune regulation. Of importance was the evidence found for "SAWA and R-Para" induced IFN-γ responses in predicting resistance.