Figure 2: Possible role of basophils in secondary immune responses against GI helminths. Basophils could be directly activated by parasite antigens or take up antigen through parasite-specific IgE antibodies developed in previous infections. IL-4, IL-13, IL-6, and BAFF, released by activated basophils, stimulate antibody production from B cells and may enhance Th2-associated immune responses. It remains to be determined if these mechanisms take place in vivo. SM: soluble mediators.