title: Specific association of retroviral envelope protein, p15E, with human cell surfaces.
abstract: Experiments were carried out to analyze the binding sites on human cells for highly purified retroviral protein p15E isolated from Feline Leukemia Virus, Rickard Strain. Binding of 125I-labeled p15E was tested with surfaces of human peripheral blood lymphocytes and 3 cell lines, Raji, MOLT-4, and U-937. 125I-labeled p15E showed specific binding to human peripheral blood lymphocytes. In addition, all of the cell lines tested showed binding of 125I-labeled p15E. Using U-937 cells, we characterized the interaction between p15E and the surface of these cells, and showed that the binding was specific by the following 3 different sets of evidence: (i) in equilibrium binding experiments, 18,000 binding sites with a dissociation constant of 2 x 10(-9) M were present on U-937 cells; (ii) trypsin or N-glycanase treatment decreased the binding sites of 125I-labeled p15E; and (iii) by affinity chromatography using p15E or BSA Sepharose columns, the isolated membranes of 125I-labeled U-937 cells previously treated with Triton X-100 showed a significantly higher binding to the p15E column than to the BSA column.
authors.affiliation: All Children's Hospital, University of South Florida, St. Petersburg 33701.
authors.forename: T
authors.initials: T
authors.lastname: Kizaki
authors.forename: M
authors.initials: M
authors.lastname: Mitani
authors.forename: G J
authors.initials: GJ
authors.lastname: Cianciolo
authors.forename: M
authors.initials: M
authors.lastname: Ogasawara
authors.forename: R A
authors.initials: RA
authors.lastname: Good
authors.forename: N K
authors.initials: NK
authors.lastname: Day
mesh_terms: D000581:Amidohydrolases / Q000494:pharmacology; D001665:Binding Sites; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D006801:Humans; D007108:Immune Tolerance; D007700:Kinetics; D005256:Leukemia Virus, Feline / Q000276:immunology / Q000378:metabolism; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D011485:Protein Binding; D015682:Retroviridae Proteins, Oncogenic / Q000276:immunology / Q000378:metabolism*; D014357:Trypsin / Q000494:pharmacology; D014759:Viral Envelope Proteins / Q000276:immunology / Q000378:metabolism*
chemical_list: D015682:Retroviridae Proteins, Oncogenic; D014759:Viral Envelope Proteins; C051525:feline leukemia virus protein p15E; D014357:Trypsin; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase