FIG. 2.

Nef increases replication of R5-tropic, X4-tropic, and dualtropic HIV-1 NL4-3 V3 variants in human PBMC. Unstimulated PBMC were infected with HIV-1 variants containing intact nef genes (filled symbols) and either a deletion (A) or a premature stop codon (B) in nef (empty symbols) immediately after isolation and stimulated 3 days later. Virus production was monitored by a reverse transcriptase (RT) assay. Results were derived from a single experiment using PBMC from two different donors. Similar results were obtained in five independent experiments with different virus stocks and PBMC from different donors. PSL, photon-stimulated light emission.