U.V. Enhanced Reactivation of U.V.- and γ-irradiated Adenovirus in Normal Human Fibroblasts

Publisher Website
Google Scholar
Abstract
An enhanced reactivation (UVER) of U.V.-irradiated as well as of γ-irradiated human adenovirus type 2 (Ad 2) was detected following infection of normal human fibroblasts which had been pre-irradiated with U.V. light. U.V.-irradiated or non-irradiated fibroblasts were infected with either non-irradiated or irradiated Ad 2, and at 48 hours after infection cells were examined for the presence of viral structural antigens (Vag) using immunofluorescent staining. Results obtained using 5 different normal fibroblast strains showed that irradiation of host monolayers with 10 J/m2 immediately prior to infection gave a U.V. enhanced reactivation (UVER) factor ± standard error equal to 3·1 ± 1·2 for virus U.V.-irradiated with 1·2 × 103 J/m2, and 2·1 ± 0·5 for virus γ-irradiated with 2 × 104 Gy. For a fixed survival of about 5·9 × 10−2 for irradiated virus, the efficiency of UVER for γ-irradiated virus was about 0·18, slightly less than the value of about 0·24 obtained for U.V.-irradiated virus. The results of time course experiments indicated that while U.V.-irradiation of normal host monolayers prior to infection gave rise to an increased rate of Vag formation for infection by unirradiated Ad 2, U.V.-irradiation of the cells increased the proportion of cells able to repair U.V.-damaged virus as well as allowing an earlier onset and/or increased rate of synthesis of Vag from a U.V.-damaged template. Similar experiments involving γ-ray enhanced reactivation (γ-RER) of irradiated Ad 2 indicated that γ-RER and UVER may operate, in part at least, by different mechanisms in normal human cells.

This publication has 41 references indexed in Scilit: