Stimulation of DNA Synthesis in Human and Hamster Cells by Human Adenovirus Types 12 and 5. ∗

Abstract

Summary

The effect of adeno-12 and adeno-5 viruses on the incorporation of thy-midine-H³ by cultures of human KB cells, newborn hamster kidney cells, and hamster embryo cells was investigated by radioautog-raphy. In KB cultures, infection with either adeno-5 or adeno-12 virus significantly increased the percentage of labelled cells, but the number of silver grains per labelled cell was somewhat lower than for control cultures. In hamster kidney cells, infection with either adeno-5 or adeno-12 decreased the mitotic index but significantly increased both the percentage of labelled cells and the intensity of label per labelled cell. Intranuclear viral inclusion bodies were formed in as high as 90% of the hamster kidney cells infected with adeno-5, which replicates in hamster cells. The incorporated label was closely associated with the intranuclear viral inclusion bodies. No viral inclusion bodies were found in the hamster kidney cells infected with adeno-12, which has an incomplete growth cycle in hamster cells. Hamster embryo cultures contained only a small percentage of epithelial cells and it was only in these that the intranuclear viral inclusion bodies were found following infection with adeno-5. Fibroblastic cells, and therefore hamster embryo cultures, were much less susceptible to adenovirus-5 (and probably to adeno-12) than the predominantly epithelial hamster kidney cultures. The percentage of labelled cells following infection of hamster embryo cultures with either adeno-5 or adeno-12 increased only slightly as compared to the hamster kidney cultures.

That viral DNA is formed even in the abortive infection of hamster cells with adeno-12 is suggested by a) decreased mitotic index but increased DNA synthesis induced by either adeno-5 or adeno-12, and b) association of the incorporated DNA-label with the viral intranuclear inclusions of hamster cells infected with adeno-5.