Identification of a purified complement-fixing antigen as the Epstein-Barr-virus determined nuclear antigen (EBNA) by its binding to metaphase chromosomes.
A soluble complement-fixing antigen carried by Epstein-Barr virus (EBV)-transformed human cells has been previously extracted from cell nuclei and purified by DNA-cellulose chromatography [Luka, J., Siegert, W. & Klein, G. (1977) J. Virol., in press]. On addition of this antigen to methanol/acetic acid-fixed metaphase chrmosomes, followed by exposure to human sera containing antibodies against the EBV-determined nuclear antigen (EBNA), brilliant positive staining was obtained by anti-complement immunofluorescence. There was no staining after exposure to EBV-negative sera. Moreover, a nuclear protein fraction, prepared from an EBV-negative cell line in an analogous fashion, failed to induce the staining reaction. These data identify the soluble purified antigen as the EBV-determined nuclear antigen. The purified antigen has a molecular weight of 174,000 +/- 15,000, as determined by sucrose gradient centrifugation and gel filtration experiments. In neutral buffers containing 0.5-1.0 M NaCl, the antigen dissociates into a form of approximately one-half the original molecular weight with retained complement-fixing activity. This "monomer" has a molecular weight of 98,000 +/- 8,000.
D000956:Antigens, Viral / Q000302:isolation & purification; D001666:Binding Sites, Antibody; D002460:Cell Line; D002875:Chromosomes / Q000276:immunology; D003168:Complement Fixation Tests; D005455:Fluorescent Antibody Technique; D004854:Herpesvirus 4, Human / Q000276:immunology*; D007621:Karyotyping; D008970:Molecular Weight; D013194:Staining and Labeling
D000956:Antigens, Viral