A first-generation packaging cell line for Epstein-Barr virus-derived vectors.

On the basis of the B lymphotropic Epstein-Barr virus (EBV), we have constructed a virus-free packaging cell line that allows encapsidation of plasmids into herpesvirus particles. This cell line harbors an EBV mutant whose packaging signals have been deleted. The gene vectors, which can encompass very large, contiguous pieces of foreign DNA, carry all cis-acting elements involved in amplification and encapsidation into virus-like particles as well as those essential for extrachromosomal maintenance in the recipient cell. Although this first-generation packaging cell line suffers from unwanted recombination between the helper virus genome and gene vector DNAs, this approach opens the way to delivery and stable maintenance of any transgene in human B cells.