IMMORTALIZATION OF HUMAN PRIMARY B-LYMPHOCYTES IN-VITRO WITH DNA

Epstein-Barr virus (EBV) is a human DNA tumor virus that efficiently i mmortalizes human primary B lymphocytes in vitro. Although viral genes that are expressed in latently infected B lymphocytes have been shown to function in cellular growth control, their detailed genetic analys is has been cumbersome for two reasons. The viral genome is too large to permit genetic engineering and human primary B lymphocytes, the onl y targets for infection by EBV in vitro, are both intractable in cultu re and recalcitrant to DNA transfection. To overcome these obstacles, we have assembled all the essential genes of EBV on a single recombina nt vector molecule in Escherichia coil. We show here that this mini-EB V plasmid can yield immortalized B cells upon transfer of its naked DN A into human primary B lymphocytes. Established cell lines carry recom binant vector DNA and cannot support virus production. Because this DN A can be easily manipulated in E. coil, mutant mini-EBVs as well as fo reign genes can now be introduced and studied successfully in recipien t B lymphocytes from any human donors, These mini-EBVs therefore are p otentially useful for human gene therapy.