CD4 and infection: In the DC-CD4+ T cell co-cultures, we detected a spreading productive infection with the number of infected cells 5 days post-infection significantly greater (median (IQR) = 40 (31, 150) EGFP+ cells/104 cells; n = 5) compared to CD4+ T cells cultured alone (1.5 (1, 2.5) EGFP+ cells/104 cells, p = 0.03; Fig. 1 C).