FIG 5.
Sensitivities of HIV-1 variants with alterations of the gp41 ectodomain to neutralization by antibodies. Recombinant HIV-1 strains expressing luciferase and bearing wild-type or mutant HIV-1HXBc2 Envs were normalized by reverse transcriptase activity. Equal amounts of viruses were incubated with serial dilutions of VRC13 (A), b12 (B), b6 (C), or F105 (D) at 37°C for 1 h prior to infection of Cf2Th-CD4 CXCR4 cells. Infectivity at each concentration of antibody tested is shown as the percentage of infection without inhibitor for each particular mutant. Quadruplicate samples were analyzed in each experiment. Data shown are the means of results from 3 (A, B, and D) or 2 (C) independent experiments. The error bars represent the standard deviations.