Figure 1. Cell-based HIV-specific Ab binding system.

(A) Diagram depicts HIV-1 pNL4.3 construct with mCherry expressed in place of HIV Nef with Nef expression restored by an internal ribosome entry site (IRES), Δvpu mutation disrupts the vpu initiation codon. (B) Diagram of HIV Ab binding to tetherin^high CD4⁺ Jurkat cells infected with an HIV-1 Δvpu Cherry–expressing reporter virus. (C) Graph illustrates the reproducibility of epitope detection across 3 separate binding assay replicates using 4 broadly neutralizing monoclonal antibodies (b12; PG9; 830A; 2F5) and non-neutralizing Ab A32, recognizing distinct regions and epitopes within HIV envelope. IgG from an HIV^– donor was used as a negative control for binding assay background.