CD4 and infection: The absence of IL-10, combined with NOS2 deficiency or even alone, does not provide a restriction to growth in the B6 resistant strain. Infection of 10NOS2-/-FP with M. leprae resulted in the accumulation of M. leprae-responsive CD4+ and CD8+ T cells in the granuloma and there was an infiltration of CD4+ T cells in the local nerves.