SOSIP.R6-IZ-CD40L-exposed DC prime naïve CD4+ T-cells. A. HLA-DR expression on CD4+ T-cells cultured for 5 days in the absence or presence of DC that were exposed to SOSIP.R6-IZ, SOSIP.R6-IZ-CD40L, or control stimuli was measured by FACS. Percentages of CD3+ HLA-DR+ T-cells are displayed within each graph. Relative number of T cells positive for cell surface expression of CD45RO (the percentages of positive cells are given in the text) (B), and intracellular expression of IFN-γ (C) and IL-4 (D). IL-2 (E), IFN-γ (F) and IL-4 (G) levels in the supernatant of DC-T cell co-cultures at day 5 measured by ELISA. Data are representative for three independent experiments.