A CD 4: immunoglobulin fusion protein with antiviral effects against HIV

Antibody-like molecules consisting of the human CD 4 extracellular domain fused to human IgG1 heavy chain constant regions were genetically constructed and expressed in a BHK cell stable transfectant. Purified chimeric antibodies bound to HIV particles as it was shown by immuno electron microscopy, inhibited fusions of HIV-1-infected cells with uninfected cells, neutralized HIV-1, and were able to inhibit the spread of a cellular HIV-1 infection in CD 4+ cells. Plaque reduction assays with CD 4(+)-transfected Hela-cells showed a comparable inhibition of HIV-1 and HIV-2. Inhibitory functions were enhanced in the presence of complement. HIV-1- and HIV-2-infected CD 4+ cells were efficiently lysed by a slow, complement-dependent mechanism, whereas uninfected CD 4+ cells and HLA-DR+ cells were not affected.