FIG 5.

SCIV infections elicit low-potency V2-directed antibodies that neutralize HIV-1. (A) Neutralization breadth and potency of SCIV-induced antibodies cloned from RMs T927 and T925 (indicated on the left). Fifty percent inhibitory concentrations (IC₅₀) are shown for representative lineage members (μg/mL) against pseudoviruses and SHIV strains (indicated on top). Only the most potent and cross-reactive lineages are shown (see Fig. S7A for similar results for the remaining lineages). The highest antibody concentration used was 250 μg/mL (coloring indicates relative neutralization potency; n.t., not tested). MAbs analyzed by negative stain electron microscopy are highlighted in red (heavy and light chain variable region sequences are shown in Fig. S8). (B) Epitope mapping of select cross-neutralizing MAbs. Neutralization curves are shown for three monoclonal antibodies (indicated on top and highlighted in red in panel A) against a panel of CAM13K and ZM233 mutant pseudoviruses (indicated on the right). Dashed lines indicate 50% reduction in virus infectivity (corresponding IC₅₀ values are shown in Fig. S7B).