title: Analysis of the human immunodeficiency virus type 1 envelope protein interaction with the CD4 host cell receptor.
abstract: A secreted form of human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (gp160s), expressed in HeLa cells from a vaccinia virus recombinant was analysed by velocity-gradient centrifugation and chemical cross-linking. We showed that gp160s existed predominantly as a dimer, but higher forms corresponding to trimers and tetramers were also found. Soluble CD4 (sCD4) and native CD4 expressed by recombinant vaccinia viruses were analysed by sucrose-gradient sedimentation alone or after complexing with gp160s. The sCD4 sedimented in sucrose gradients as a monomer, whereas after solubilization the native CD4 was in a dimeric state. Both forms of CD4 were able to form complexes when incubated with gp160s. In the case of the sCD4, the M(r) corresponded to a (sCD4)2-(gp160s)2 complex, whereas with CD4 the complexes were of a greater order of magnitude. HIV gp120 was secreted into the medium in a monomeric state. With sCD4 it gave a one-to-one complex, whereas with the native CD4 high M(r) complexes were formed. The importance of the oligomeric state of the virus- and cell-receptor proteins are discussed regarding their avidities.
authors.affiliation: Institut Pasteur de Lyon, France.
authors.forename: E
authors.initials: E
authors.lastname: Malvoisin
authors.forename: F
authors.initials: F
authors.lastname: Wild
mesh_terms: D000911:Antibodies, Monoclonal; D015704:CD4 Antigens / Q000737:chemistry / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D003432:Cross-Linking Reagents; D015686:Gene Products, env / Q000737:chemistry / Q000378:metabolism*; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000378:metabolism; D019302:HIV Envelope Protein gp160; D015497:HIV-1 / Q000737:chemistry* / Q000254:growth & development / Q000302:isolation & purification; D006367:HeLa Cells; D006801:Humans; D008970:Molecular Weight; D011233:Precipitin Tests; D011485:Protein Binding; D011498:Protein Precursors / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014616:Vaccinia virus / Q000235:genetics
chemical_list: D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D003432:Cross-Linking Reagents; D015686:Gene Products, env; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; D019302:HIV Envelope Protein gp160; D011498:Protein Precursors; D011994:Recombinant Proteins; C076613:recombinant soluble CD4