Close encounters of the second type

摘要

To combat intestinal worms, mammals rely on adaptive immune responses mediated by T cells. However, it seems that, initially, innate immune cells mimic T-cell activity, while T cells get ready for action.rnGastrointestinal infection with worms induces a type-2 immune response that promotes expulsion of the parasites. Type-2 immunity includes the recruitment of specialized white blood cells such as eosinophils, the production of antibodies of the IgE class, and the secretion of mucus by goblet cells. It has long been known that the immune mediators (cytokines) produced by T cells coordinate these responses. But T cells need several days to develop type-2 immunity because they first have to be selected for reactivity to parasite antigens. Three papers - including two on pages 1362 and 1367 of this issue - now report that innate immune cells also have an essential role in mediating type-2 immunity to helminth worms by mimicking the role of T cells, albeit more promptly and less specifically.