FIG. 5.
Epitope specificity of HIV-2KR.X7 YU2 V3 chimera neutralization by HIV-1 V3 MAbs. HIV-2KR.X7 YU2 V3 neutralization by 447-52D or F425 B4e8 is competed by V3JR-FL 24-mer peptide (A), V3YU2 24-mer peptide (B), or by Fc-V3B FP or Fc-V3C FP (C). V3 peptides and fusion protein (FP) competitors are shown in Table 2. For all experiments, fivefold serial dilutions of HIV-1 MAbs were combined with peptide or fusion protein and incubated at 37°C for 30 min. Virus was then added and incubated at 37°C for 1 h, and the mixture was transferred to TZM-bl reporter cells. The final peptide and fusion protein concentrations in all wells were 50 μg/ml and 10 μg/ml, respectively. Luciferase expression was assessed 48 h later and was normalized to that in the absence of antibody or inhibitor. Scrambled (scr) V3 peptide, fusion proteins lacking complete or partial V3 sequences, and medium-only controls were included.