Adenoviral vector cytotoxicity depends in part on the transgene encoded

First-generation adenoviral vectors induce G(2)/M arrest and cell death at high multiplicities of infection (m.o.i.'s) in vitro. It is unclear whether this cytotoxicity is entirely adenoviral gene related or influenced in par t by the encoded transgene. We examined this question in epithelial cells u sing seven vectors at relatively low (50) or higher (200) m.o.i.'s. The vec tors contained no transgene (+/-promoter), transgenes encoding a cytoplasmi c reporter protein (two luciferase constructs; P-galactosidase), or transge nes encoding a secretory protein (alpha 1-antitrypsin; growth hormone). Aft er 24 h with a m.o.i. of 50, vectors encoding cytoplasmic reporter proteins led to greatest cytotoxicity (similar to 35-40% cells in G(2)/M). Vectors without a transgene resulted in lower cytotoxicity (similar to 15%, minus, or 23%, plus promoter, cells in G(2)/M). Vectors encoding secretory protein s led to similar to 22-25% cells in G(2)/RI. A similar pattern resulted whe n cell number was measured. Results were unrelated to the steady-state leve ls of transgene product. At the higher m.o.i., all vectors caused substanti al growth retardation, This is the first demonstration that adenoviral vect or-induced cytotoxic effects are in part related to the transgene encoded. (C) 2000 Academic Press.