FIG 6 .

Analysis of the expression and viral entry efficiency of the different HIV-1-Env proteins from LTNP-EC and control patients. (A) Gp120 partial amino acid sequences of AS7 virus and the mutants derived in this AS7 virus backbone (AS7_I140T, AS7_V279A, and AS7_I400T) are shown and compared to the LTNP_1 clone 12 gp120 amino acid sequence from one of the cluster viruses. (B) Luciferase-based assay of viral entry and infection in permissive CEM.NKR-CCR5 cells by nonreplicative HIV-1 luciferase reporter pseudoviruses bearing viral AS7 Env and the AS7 mutants shown in panel A and the control BaL.01 Env strain (light gray bars). Nonproductive infection values (baseline) are obtained with a neutralizing anti-CD4 MAb (5 μg/ml), under the same experimental conditions. The quality of viral production and the specificity of CD4 for neutralizing HIV-1 early infection are indicated by the data obtained by using HIV-1 pseudovirus bearing the VSV-G Env. Data are values from 6 independent experiments carried out in triplicate. a.u., arbitrary light units.