Latency can be established in vitro by direct infection of resting CD4+ T-cells in the presence of stimuli, including the chemokine CCL19 [4–6]; high viral titres with or without spinoculation [7–11]; or culturing T-cells in contact with myeloid dendritic cells [mDC, [12]] or endothelial cells [13]. This evidence concerns the gene CD4 and infection.