Purification of biologically active Epstein-Barr virus by affinity chromatography and non-ionic density gradient centrifugation.

Epstein-Barr virus was purified by affinity chromatography on ricin agglutinin Sepharose followed by non-ionic density gradient centrifugation on Nycodenz. The purified virus was highly active in three biological assays: stimulation of immunoglobulin synthesis by B lymphocytes, transformation of B lymphocytes, and superinfection of Raji cells, as well as in an indirect immunofluorescent binding assay. Electron microscopy revealed intact viral particles free of contaminating membranous structures. CsCl density gradient analysis of nick-translated DNA showed material only at the expected viral density with no detectable material at the density of cellular DNA. SDS gel electrophoresis of radioiodinated virus revealed the characteristic viral polypeptides. This method produces highly purified, biologically active virions with an overall recovery of about 30%.