Increases in Human T Helper 2 Cytokine Responses to<i>Schistosoma mansoni</i>Worm and Worm‐Tegument Antigens Are Induced by Treatment with Praziquantel

Abstract

Levels of Schistosoma mansoni-induced interleukin (IL)-4 and IL-5 and posttreatment levels of immunoglobulin E recognizing the parasite's tegument (Teg) correlate with human resistance to subsequent reinfection after treatment. We measured changes in whole-blood cytokine production in response to soluble egg antigen (SEA), soluble worm antigen (SWA), or Teg after treatment with praziquantel (PZQ) in a cohort of 187 individuals living near Lake Albert, Uganda. Levels of SWA-induced IL-4, IL-5, IL-10, and IL-13 increased after treatment with PZQ, and the greatest relative increases were seen in the responses to Teg. Mean levels of Teg-specific IL-5 and IL-10 increased ~10-15-fold, and mean levels of IL-13 increased ~5-fold. Correlations between the changes in cytokines suggested that their production was positively coregulated by tegumentally derived antigens. Levels of SEA-, SWA-, and Teg-induced interferon- gamma were not significantly changed by treatment, and, with the exception of IL-10, which increased slightly, responses to SEA also remained largely unchanged. The changes in cytokines were not strongly influenced by age or intensity of infection and were not accompanied by corresponding increases in the numbers of circulating eosinophils or lymphocytes.