Antibody from patients with acute human immunodeficiency virus (HIV) infection inhibits primary strains of HIV type 1 the presence of natural-killer effector cells

The partial control of viremia during acute human immunodeficiency virus ty pe 1 (HIV-1) infection is accompanied by an HIV-1-specific cytotoxic T-lymp hocyte (CTL) response and an absent or infrequent neutralizing antibody res ponse. The control of HIV-1 viremia has thus been attributed primarily, if not exclusively, to CTL activity. In this study, the role of antibody in co ntrolling viremia was investigated by measuring the ability of plasma or im munoglobulin G from acutely infected patients to inhibit primary strains of HIV-1 in the presence of natural-killer (NK) effector cells. Antibody that inhibits virus when combined with effector cells was present in the majori ty of patients within days or weeks after onset of symptoms of acute infect ion. Furthermore, the magnitude of this effector cell-mediated antiviral an tibody response was inversely associated with plasma viremia level, and bot h autologous and heterologous HIV-1 strains were inhibited. Finally, antibo dy from acutely infected patients likely reduced HIV-1 yield in vitro both by mediating effector cell lysis of target cells expressing HIV-1 glycoprot eins and by augmenting the release of beta -chemokines from NK cells. HIV-1 -specific antibody may be an important contributor to the early control of HIV viremia.