As an alternative strategy to deplete CD4 T-cells in the lungs during UgCl223 infection, we mimicked the loss of CD4-expressing T-cells observed in HIV by crossing CD4-Cre and Cre-inducible diphtheria toxin receptor (iDTR) mice to generate CD4DTR mice (Buch et al., 2005) (Figure 6A). The gene discussed is CD4; the disease is infection.