Modulation of gene expression after replication-deficient, recombinant adenovirus-mediated gene transfer by the product of a second adenovirus vector.

To regulate gene expression following adenovirus-mediated gene transfer, a strategy was devised utilizing co-infection with two separate adenovirus vectors designed such that the product of one vector modulated the promoter of the second vector. To evaluate this strategy, AdEGR1.TNF, an adenovirus expressing tumor necrosis factor-alpha (TNF) under the control of the early growth response 1 (EGR1) promoter, was used to regulate a transcription unit in AdIL8.beta gal, an adenovirus vector in which the TNF sensitive interleukin-8 (IL-8) promoter drives the expression of beta-galactosidase (beta-gal). Following infection of HS24 cells with AdIL8.beta gal, addition of TNF to the culture induced the expression of beta-gal. Infection of HS24 cells with AdEGR1.TNF resulted in a dose-dependent secretion of TNF. Little beta-gal was produced following co-infection of the cells with the control vector AdCMV.Null (expressing no specific gene) and AdIL8.beta gal. In contrast, co-infection with AdIL8.beta gal and AdEGR1.TNF demonstrated, for a given dose of AdIL8.beta gal, increasing amounts of beta-gal expression dependent on the dose of AdEGR1.TNF. This model suggests control of gene expression in adenovirus-mediated gene transfer can be regulated by utilizing a promoter-gene expression cassette in one vector that modulates the expression of a promoter-gene expression cassette in a second vector.