Envelope Glycoprotein Determinants of HIV -1 Induced Membrane Fusion

In 1983 the isolation of a previously unknown human retrovirus was first associated with a newly recognized acquired immune deficiency syndrome (AIDS), characterized by unusual opportunistic infections and malignancies (II). Subsequently repeated retrovirus isolations from individuals with AIDS or from individuals known to be at risk of acquiring this disease were reported (53,99,133). These retroviruses were characterized as members ofa separate group of primate lentiviruses, the human immunodeficiency viruses (HIV). They were indeed identified as the etiological agents of AIDS (29,143,153). Within this group two major subtypes are presently distinguished: HIV-I and HIV-2 (26,27,64). The lentiviruses identified to date which may cause AIDS like syndromes in infected animals include simian immunodeficiency virus (SIV) and feline immunodeficiency virus (FIV). Both SIV infection of macaques and FIV infections of cats are presently used as animal models for HIV infections in humans (97). Here a concise overview of the biology of HI V-I is presented, with special attention for the process of HIV-I induced membrane fusion which is at the basis of viral entry and syncytium formation.