Interleukin‐9 is involved in host protective immunity to intestinal nematode infection

摘要

AbstractMurine studies have demonstrated that, as with other nematodes, infection with the intestinal nematodeTrichinella spiralisis associated with a pronounced intestinal mastocytosis, eosinophilia and an elevation in serum levels of total IgE. Both interleukin (IL)‐4 and IL‐5 are clearly important in the generation of IgE responses and eosinophilia, respectively, but the control of mucosal mastocytosisin vivois not as well defined. Mucosal mast cells appear to be particularly important with regard toT.spiralisinfections as there is good evidence to suggest their involvement in expulsion of the parasite from the host. In this study we examined the effect of the overproduction of the Th2 cytokine IL‐9 on infection with this nematode. We demonstrate that naive IL‐9‐transgenic mice have an intense intestinal mastocytosis and high serum levels of mouse mast cell protease‐1. Moreover, upon infection high titers of parasite‐specific IgG1 were observed with a heightened mast cell response, which was associated with the rapid expulsion ofT. spiralisfrom the gut. Furthermore, as depression of this mast cell response, using anti‐c‐kitantibodies, resulted in the inability of these mice to expel the parasite, this study clearly demonstrates an activity of IL‐9 on mucosal mastocytosis and the host protective imm