IFNG and infection: However, in B6.WT mice the frequency of IFNγ-producing cells did not increase significantly until d 10 of L. major infection; whereas a slight but significant increase in the frequency of IFNγ-producing CD4 cells was already detected on d 6 post infection (p.i.)in B6.CCR6−/− mice (Figure 3D) while the proportion of total CD4 cells in the lymph nodes was not different in the two strains (Figure S2B).