IL17A and infection: As shown in Figure 3, C57BL/6 and IL-22 KO mice vaccinated with mc2-CMX exhibited higher total cell number (Figure 3) levels of CMX specific CD4+IFN-γ+ T cells compared to the animals that were only infected with M. tuberculosis. Whereas the IL-17 KO mice that were vaccinated and challenged with M. tuberculosis presented CD4+IFN-γ+ response levels similar to that observed with infection of IL-17 unvaccinated mice, which in turn presented response levels similar to the other genetic background mice (compare diamond filled bars of Figure 3).