125,126 Moreover, mouse immunization studies of a potential M. tuberculosis vaccine revealed that lung-accumulating IL-17-secreting T cells encourage the generation of chemokines that attract Th1 cells to regulate infection.97 These results potentially reflect Th17 cell plasticity in vivo, and they also suggest a collaborative effect of IL-17 on the IFN response to various bacterial infections. Here, IL17A is linked to infection.