Characterization of anti-HIV-1 neutralizing and binding antibodies in chronic HIV-1 subtype C infection.

Abstract Neutralizing (nAbs) and high affinity binding antibodies may be critical for an efficacious HIV-1 vaccine. We characterized virus-specific nAbs and binding antibody responses over 21 months in eight HIV-1 subtype C chronically infected individuals with heterogeneous rates of disease progression. Autologous nAb titers of study exit plasma against study entry viruses were significantly higher than contemporaneous responses at study entry ( p =0.002) and exit ( p =0.01). NAb breadth and potencies against subtype C viruses were significantly higher than for subtype A ( p =0.03 and p =0.01) or B viruses ( p =0.03; p =0.05) respectively. Gp41-IgG binding affinity was higher than gp120-IgG ( p =0.0002). IgG–FcγR1 affinity was significantly higher than FcγRIIIa ( p p p