title: Full-length CD4 electroinserted in the erythrocyte membrane as a long-lived inhibitor of infection by human immunodeficiency virus.
abstract: Recombinant full-length CD4 expressed in Spodoptera frugiperda 9 cells with the baculovirus system was electroinserted in erythrocyte (RBC) membranes. Of the inserted CD4, 70% was "correctly" oriented as shown by fluorescence quenching experiments with fluorescein-labeled CD4. The inserted CD4 displayed the same epitopes as the naturally occurring CD4 in human T4 cells. Double-labeling experiments (125I-CD4 and 51Cr-RBC) showed that the half-life of CD4 electroinserted in RBC membrane in rabbits was approximately 7 days. Using the fluorescence dequenching technique with octadecylrhodamine B-labeled human immunodeficiency virus (HIV)-1, we showed fusion of the HIV envelope with the plasma membrane of RBC-CD4, whereas no such fusion could be detected with RBC. The dequenching efficiency of RBC-CD4 is the same as that of CEM cells. Exposure to anti-CD4 monoclonal antibody OKT4A, which binds to the CD4 region that attaches to envelope glycoprotein gp120, caused a significant decrease in the dequenching of fluorescence. In vitro infectivity studies showed that preincubation of HIV-1 with RBC-CD4 reduced by 80-90% the appearance of HIV antigens in target cells, the amount of viral reverse transcriptase, and the amount of p24 core antigen produced by the target cells. RBC-CD4, but not RBCs, aggregated with chronically HIV-1-infected T cells and caused formation of giant cells. These data show that the RBC-CD4 reagent is relatively long lived in circulation and efficient in attaching to HIV-1 and HIV-infected cells, and thus it may have value as a therapeutic agent against AIDS.
authors.affiliation: Molecular Virology Laboratory, St. Luke's/Roosevelt Hospital Center, New York, NY.
authors.forename: M
authors.initials: M
authors.lastname: Zeira
authors.forename: P F
authors.initials: PF
authors.lastname: Tosi
authors.forename: Y
authors.initials: Y
authors.lastname: Mouneimne
authors.forename: J
authors.initials: J
authors.lastname: Lazarte
authors.forename: L
authors.initials: L
authors.lastname: Sneed
authors.forename: D J
authors.initials: DJ
authors.lastname: Volsky
authors.forename: C
authors.initials: C
authors.lastname: Nicolau
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015704:CD4 Antigens / Q000097:blood* / Q000276:immunology; D002449:Cell Aggregation; D004560:Electricity; D004910:Erythrocyte Membrane / Q000276:immunology* / Q000382:microbiology; D006678:HIV / Q000502:physiology*; D015699:HIV Envelope Protein gp120 / Q000276:immunology; D015497:HIV-1 / Q000276:immunology / Q000502:physiology; D006207:Half-Life; D006801:Humans; D008561:Membrane Fusion; D011817:Rabbits; D011994:Recombinant Proteins; D013601:T-Lymphocytes / Q000276:immunology / Q000382:microbiology
chemical_list: D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D015699:HIV Envelope Protein gp120; D011994:Recombinant Proteins