Cellular immune responses of a Senegalese community recently exposed to Schistosoma mansoni: correlations of infection level with age and inflammatory cytokine production by soluble egg antigen-specific cells

A recently reported epidemic of Schistosoma mansoni infection in Senegal pr ovided an opportunity to study the dynamics of the development of immunity to human schistosomiasis. We report here on the cell-mediated immune respon se in a population of 99 females and 95 males, with particular emphasis on the relationship between intensity of infection and age. Rie found that the intensity of infection correlated negatively with age in females but not i n males. In men and women, both Th1-and Th2-type cytokines were detected up on in vitro stimulation of PBMCs with soluble egg antigen (SEA) or soluble adult worm antigens (SWAP). In the female group, SEA-induced PBMC prolifera tion was associated with the production of IFN-gamma, IL-2 and IL-5, all of which correlated negatively with intensity of infection. Most cytokine pro duction correlated positively with age. Spontaneous production of TNF-alpha , IL-6 and IL-10 was higher in the infected population than in an uninfecte d control group. Our results suggest that immunity to infection could be mo re pronounced in the female population and associated with a Th0/1 + 2 patt ern of cytokine secretion mediated by soluble egg antigen (SEA).