CD4 and infection: Immunological characterization showed no significant differences in the percentages of myeloid or lymphoid cell types in the lungs of Cbs+/− and WT mice prior to, or 3 weeks after infection with Mtb. However, 8 weeks after infection, WT mice exhibited increased percentages of neutrophils, macrophages, CD4+ cells, and CD4+IFN-γ+ cells in the lung compared to Cbs+/− mice (Figure 5).