IL9 and parasitic infectious disease: Subsequent studies implicated a protective role for IL-9 in TH2-driven responses during murine parasitic infections [153], [154], with IL-9 levels in mesenteric lymph nodes correlating with expansion of TH2 cell populations and a requirement of IL-9 for CSR to the “type-2” antibody isotypes IgG1 and IgE [155], [156].