EFFECT OF ANTI-V3 ANTIBODIES ON CELL-FREE AND CELL-TO-CELL HUMAN-IMMUNODEFICIENCY-VIRUS TRANSMISSION

The present study was undertaken to compare the effects of a type-spec ific (HIV-1 MN) anti-V3 antibody on in vitro human immunodeficiency vi rus (HIV) infection of peripheral blood mononuclear cells in systems o f cell-free versus cell-to-cell transmission of virus. Anti-V3 antibod y completely prevented HIV-1 infection when cell-free virus was the so le mechanism of infection. A significant reduction of the neutralizing activity of the anti-V3 antibody was observed when infectivity was de pendent on both cell-free and cell-to-cell mechanisms of infection. Fu rthermore, when cell-to-cell transfer of virions was the primary mecha nism of HIV-1 infection, inhibition of HIV-1 infection was not observe d. Therefore, a potent neutralizing antibody with a single epitope spe cificity failed to effectively control dissemination of a persistent H IV-1 infection in a system characterized predominantly by cell-to-cell transfer of virus.