Susceptibility and resistance to Schistosoma mansoni reinfection: Parallelcellular and isotypic immunologic assessment

Cellular and humoral immune responses to Schistosoma mansoni antigen prepar ations were evaluated in individuals presumed to be susceptible or resistan t to reinfection after chemotherapeutic cure. A consistent proliferative in crease in the response to soluble egg antigen (SEA) was observed post-treat ment in both the susceptible and resistant groups. However, this change was not related to resistance. Isotype studies showed that IgM antibody levels to soluble worm antigen preparation (SWAP) and cercariae antigens were sig nificantly higher in the resistant group than in the susceptible group. Pos t-treatment, an increase in IgE anti-SWAP and anti-schistosomular tegument (STEG) responses and a decrease in IgG4 anti-SEA and anti-STEG responses we re observed in the resistant group. These finding are similar to those we h ave reported previously for a putative resistant group termed endemic norma ls, and are compatible with immunologic studies in different endemic areas. Together, these findings indicate that even on the population level, high IgE specificities coupled with low IgG4 specificities correlate well with d ocumented resistance to reinfection.