In fact, vaccine-induced IL-23-dependent IL-17A-producing Th17 cells populate the lung early after infection with Mtb- and in turn induce C-X-C motif ligand (CXCL)9, CXCL10, and CXCL11 chemokine expression to promote the recruitment of Th1 cells to the lung [15]. This evidence concerns the gene CXCL9 and infection.