In contrast, after infection with the hypervirulent Mtb strain HN878, IL-17A mediates early protection through induction of the C-X-C motif chemokine CXCL13, which, in turn, supports the localization of C-X-C chemokine receptor type (CXCR)5-expressing T cells within lung lymphoid follicles to ensure optimal macrophage activation and thus control of Mtb infection. This evidence concerns the gene IL17A and infection.