ISOLATION AND CHARACTERIZATION OF PACKAGING CELL-LINES THAT COEXPRESSTHE ADENOVIRUS E1, DNA-POLYMERASE, AND PRETERMINAL PROTEINS - IMPLICATIONS FOR GENE-THERAPY

Current generation adenovirus (Ad) vectors are deleted for the E1 regi on of genes and require propagation in E1 expressing 293 cells. Expres sion of genes delivered by Ad vectors into immunocompetent hosts is ge nerally transient since the current vectors are not completely replica tion defective. Viral proteins expressed by Ad vectors, in part, induc e a rapid, T cell-mediated loss of transduced cells. Introduction of t emperature-sensitive point mutations into new Ad vectors may be of lim ited usefulness in prolonging transduced gene expression in vivo. Isol ation of new Ad vectors deleted for gene required for normal Ad growth may further prevent Ad protein expression. These new vectors will nee d to be grown in 293 cells capable of coexpressing other Ad genes. Unf ortunately, many of the Ad genes are toxin when coexpressed in 293 cel ls. We describe the isolation of E1 expressing 293 cells which also ex press both the Ad polymerase and preterminal proteins, both of which a re essential to normal Ad growth. The isolation of new Ad vectors dele ted for the E1, polymerase and preterminal proteins are predicted to h ave many advantageous properties, including the prolongation of transd uced foreign gene expression in vivo.