Fusion of human immunodeficiency virus type 1 (HIV-1) with human cells as measured by membrane fluorescence dequenching (DQ) method; roles of HIV-1-cell fusion in AIDS pathogenesis.

HIV-1, the primary etiologic agent of AIDS, is a non-transforming human retrovirus which shares many physical and functional characteristics with viruses from the lentivirus family. One of these characteristics is that HIV-1 infection has profound cytopathic effects on host cells. Studies by the membrane fluorescence dequenching (DQ) method using HIV-1 virions labeled with octadecylrhodamine B-chloride (R-18) have shown that HIV-1 enters host cells by a process of fusion between viral envelope and target cell plasma membrane. The parameters of HIV-1-cell fusion are similar to those established for paramyxoviruses and other enveloped fusogenic viruses. HIV-1-cell fusion requires the presence of surface CD4 receptors on human T cell and monocytes, but not on human glial and neuronal cells. It is proposed that cell surface effects of HIV-1 due to the interaction between HIV-1 fusion glycoproteins and membrane receptors are major contributors to the cytopathic and pathogenic function of this virus.