Shedding and Interspecies Type Sero-reactivity of the Envelope Glycopolypeptide Gp120 of the Human Immunodeficiency Virus

Two glycopolypeptides with molecular weights 160,000 and 120,000 (gp120) are regularly recognized by human immunodeficiency virus (HIV)-specific antisera in lysates of cells persistently infected with HIV. In the present study, gp120 was characterized as the major envelope glycopolypeptide of HIV. Gp120 was identified as the external viral glycoprotein by radiosequencing and by its presence in purified virus. However gp120 was predominantly shed as a soluble protein into the culture fluid. Furthermore gp120 was precipitated by sera from horses infected with equine infectious anaemia virus (EIAV), but not by sera from uninfected animals. This may indicate conserved epitopes common to the envelopes of HIV and EIAV.