Direct detection of infectious human immunodeficiency virus type 1 (HIV-1) immune complexes in the sera of HIV-1-infected persons

Abstract

The sera of human immunodeficiency virus type 1 (HIV-1)-infected subjects were examined for the presence of infectious HIV-1-antibody complexes by their ability to infect Fc gamma receptor (Fc gamma R)-bearing cells. Infection of Fc gamma R-bearing cells by a serum in which half of the p24 antigen was present in a form of immune complexes was inhibited by aggregated human immunoglobulin. Then in studies on 22 sera, 9 sera produced p24 antigen during 14 days of culture in U937 cells. HIV-1 p24 production was inhibited or delayed by the pretreatment of cells with aggregated human immunoglobulin in 6 of the 9 sera that were infectious. These results may reflect interactions between virus-antibody complexes and Fc gamma R-bearing cells in vivo because serum itself was used as the source of virus and virus-antibody complexes. The results indicate that infectious HIV-1 immune complexes are present in the circulation of HIV-1-infected patients.