CD4 and infection: Similarly, the frequency of proliferating CD4+ T cells was significantly greater in the lesions of healer mice than in nonhealer mice 4 weeks post infection (Figure 2B, 3.0±0.6% vs 0.6±0.1%, P<0.05); in contrast the frequency of proliferating CD4+ T cells in the lymph nodes did not differ between the two strains 2 and 4 weeks post infection (Figure 2A and B).