HUMAN ERYTHROCYTES BEARING ELECTROINSERTED CD4 NEUTRALIZE INFECTION IN-VITRO BY PRIMARY ISOLATES OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-I

Human erythrocytes bearing electroinserted full-length CD4 (RBC-CD4) c an bind and fuse with a laboratory strain of human immunodeficiency vi rus type 1 (HIV-1) or with T cells infected by HIV-1. Here we show tha t RBC-CD4 neutralize primary HIV-1 strains in an assay of cocultivatio n of peripheral blood mononuclear cells (PBMC) from HIV-1-infected per sons with uninfected PBMC. RBC-CD4 inhibited viral p24 core antigen ac cumulation in these cocultures up to 10,000-fold compared with RBC alo ne. Viral p24 accumulation was inhibited equally well when measured in culture supernatants or in cell extracts. The inhibition was dose-dep endent and long-lived. Two types of recombinant CD4 tested in parallel were largely ineffective. The neutralization of primary HIV-1 by RBC- CD4 in vitro was demonstrated in PBMC cultures from 21 of a total of 2 3 patients tested at two independent sites. RBC-CD4 may offer a route to blocking HIV-1 infection in vivo. (C) 1996 by The American Society of Hematology.