The mice with D2 BP also had significantly lower numbers of p24+ cells in the mesenteric lymph node than mice carrying 2G12 BP (Figure 3C), although neither backpack significantly protected the spleen from HIV-1 infection (Figure 3D for the percentage of CD4 T cells and Figure S2C for the number of p24+ cells). The gene discussed is CD4; the disease is HIV-1 infection.