FIG. 5.
Neutralization of HIV-1JR-FL pseudovirus by rabbit antisera is predominantly mediated by non-V3, gp120-directed antibodies. (A) BSA (filled triangles)-, V3 peptide (open circles)-, or gp120 (open diamonds)-coupled cyanogen bromide-Sepharose beads were used to deplete a rabbit preimmune serum pool spiked with V3-specific MAb PA1 (i, ii) or the CD4-IgG2 molecule (iii) before assay by gp120 binding ELISA (i, iii) or V3 peptide ELISA (ii). The nondepleted serum was also assayed (filled squares). (iv) Rabbit final blood drawing sera from the pilot study, 5695-3 (filled bars), and follow-up study, 228 (dark grey bars), 236 (light grey bars), and 241 (open bars), were left untreated (Pre) or depleted using BSA-, V3-, or gp120-coupled beads before determination of midpoint binding titers against gp120 or V3 peptide by ELISA as indicated. (B) Untreated and bead-treated sera 5695-3 and 241 were also used in pseudovirus neutralization assays against HIV-1JR-FL (upper parts) or HIV-1MN (lower parts). Bars represent serum dilutions of 1:10 (filled bars), 1:40 (grey bars), and 1:160 (open bars). Representative data were derived from two or three experiments.