Long-term episomal gene delivery in human lymphoid cells using human and avian adenoviral-assisted transfection

Human B-lymphoblastoid cells transformed by Epstein-Barr virus (EBV), a common source of established human cell lines, are generally refractory to standard DNA transfection methods. We report here the use of human and chicken adenoviruses for the stable delivery of plasmid DNA carrying the latent origin of replication, oriP, from EBV into human B-lymphoblastoid cells. Long-term hygromycin-resistant transformants of human lymphoblastoid cells belonging to the genetically unstable inherited disease Fanconi's anemia were obtained by adenoviral-assisted transfection of plasmid DNA complexed to either human adenovirus type 5 (Ad5) or avian adenovirus type 1 (CELO). Successful long-term transformation of human lymphoblastoid cells was unrelated to the efficiency of short-term transfection as measured by the transient expression level of a reporter lacZ gene. The human or avian adenoviral binary conjugates, with no other cell ligand, were sufficient for stable cell transformation. The amount of DNA established in the human B-cell transformants was approximately 100-fold higher with the CELO virus. We conclude that Ad5-assisted transfection is more suitable for transient gene expression studies in human lymphoblastoid cells, while CELO-assisted transfection appears the method of choice for stable genetic transformation of such cells. Such differential short- and long-term gene delivery strategy with Ad5 and CELO may be useful in gene therapy of human B cells involving cancers and inherited diseases, respectively.