DC transmit HIV-1 with equal efficiency to Th0, Th1 and Th2 cells. (A) In vitro generated polarized populations of Th1 and Th2 cells, or an unbiased population (Th0), were analyzed for intracellular cytokines IFNγ and IL-4 by FACS. The percentage single and double positive cells is indicated. (B) Th0, Th1 and Th2 cells were co-cultured with R5 or X4 virus-loaded DC in a single-cycle transmission assay to determine the transmission efficiency. Different DC subsets were used: DC1 that stimulate TN cells to develop into Th1 cells, DC2 that induce Th2 cells, or DC0 that induce an unpolarized response (Th0). The percentage CA-p24+ T cells was determined by FACS 2 days post transmission. Error bars represent standard deviations. * p < 0.05 ; ** p < 0.01; *** p < 0.001.