Pseudotyped virions and single round infection
293T cells (1 × 107) were transfected with pNL4-3.Luc.R-E- or pNL4-3.FLAG-Tat.R-E- (10 µg) together with pHXB2 Env (10 µg), and 48-h post-transfection cell supernatant was collected. Enzyme-linked immunosorbent assay (ELISA) using anti-p24 antibody measured virion concentration. PBMCs, Jurkat or U937 cells (5 × 107) were infected with HXB2 Env-pseudotyped virions (500 ng of p24) by spinoculation, as previously described (50).