At 12 weeks post-primary immunization (at the time of infection), although quantitatively, both BCG and B/D vaccinated animals exhibited a comparable frequency of CD4 T cells (data not shown), qualitatively, a marked functional heterogeneity was observed in terms of their ability to produce IFNγ, TNFα and IL2 (Fig. 6B). The gene discussed is CD4; the disease is infection.