Monoclonal Antibodies that Neutralize HIV–1 Virions and Inhibit Syncytium Formation by Infected Cells

Abstract

Several hybridomas secreting neutralizing monoclonal antibodies against the AIDS virus, human immunodeficiency virus type 1 (HIV–1), have been developed by immunizing mice with inactivated HIV–1 and fusing the immune spleen cells with myeloma cells. The monoclonal antibodies are specific to epitopes of the viral envelope protein, gp120, as assessed by enzyme–linked immunosorbent assays and Western immunoblotting. They bind to viral antigens on the surface of HIV–1–infected T cells, and effectively inhibit the infection of T cells by free virions in vitro at sub–nanomolar concentrations. They also inhibit the fusion between uninfected and infected cells—a process implicated in viral transmission and T cell death. These results suggest that the same epitopes of gp120 may be involved in both the binding of HIV–1 virions to target cells and the interaction between HIV–1 infected and uninfected cells. The potential applications of these antibodies to understanding the critical neutralizing domains on the HIV envelope, and in treating HIV–infected individuals and patients with AIDS, are discussed.