FIG. 6.

Neutralization of the infectivity of HIV-1 primary isolates by anti-CCR5 mouse antibodies. Isolates HIV no. 36 and HIV no. 40 were subtype B, R5 tropic; isolate HIV no. 45 was subtype B, R5, R3, X4 tropic. Antibodies were affinity purified on peptide-coupled beads from mucosal IgA- and IgG-enriched fractions derived from FHV-I2 or FHV-WT antisera. In panels A, B, and C, 8 ng/ml of Igs were used. The positive control (Cntr) was the anti-human CD4 MAb SIM4. In the negative control, no antibody was added. The error bars indicate standard deviations. (D and E) Dose-response curves of infectivity reduction obtained by treating lymphocytes with the indicated concentrations of IgA or IgG antibodies from FHV-I2 or FHV-WT antisera. Since only small serum samples could be collected, the antibodies for the neutralization assay were purified from a pool of samples drawn after the fourth and fifth immunizations.