HIV: early virus-cell interactions.
Two entry mechanisms of HIV occur in both lymphocytes and macrophages incubated with purified virus suspensions: (a) direct fusion of the viral envelope with the cell membrane and (b) receptor-mediated endocytosis via clathrin-coated pits and vesicles. Both mechanisms are shown in detail in a time-interval series of electron micrographs. The two lipid bilayers of the viral envelope and of the cellular membrane usually fuse seamlessly within 1-3 min at 37 degrees C, but occasionally membrane ruptures occur, leading to rapid cytopathic effects, i.e., vacuolization and cytolysis only a few minutes later. In the course of virus-cell fusion, gp 120 is integrated into the cell membrane; subsequent syncytia formation was observed after 1 h of incubation. The core disintegrates and releases the viral ribonucleoprotein through the opening at the fusion site into the cytoplasm.
Robert Koch-Institut des Bundesgesundheitsamtes, Berlin, F.R.G.
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Grewe
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Beck
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Gelderblom
D000327:Adsorption; D002460:Cell Line; D002462:Cell Membrane / Q000382:microbiology; D002478:Cells, Cultured; D002999:Clone Cells; D003588:Cytopathogenic Effect, Viral; D004705:Endocytosis; D015699:HIV Envelope Protein gp120 / Q000032:analysis; D015700:HIV Envelope Protein gp41 / Q000032:analysis; D015497:HIV-1 / Q000502:physiology* / Q000648:ultrastructure; D015498:HIV-2 / Q000502:physiology* / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D008051:Lipid Bilayers; D008214:Lymphocytes / Q000382:microbiology* / Q000648:ultrastructure; D008264:Macrophages / Q000382:microbiology* / Q000648:ultrastructure; D008854:Microscopy, Electron
D015699:HIV Envelope Protein gp120; D015700:HIV Envelope Protein gp41; D008051:Lipid Bilayers