Activation of adenovirus type 5 latent infections of tissue culture

To study the in vitro activation of latent adenovirus type 5 infection and enhancement of virus production, primary human amnion and HEp-2 cell cultures were inoculated with low doses of virus and subsequently treated with steroid hormones, carcinogens, or a pyrogen drug 'Pyrago' containing killed cells of bacteria and fungi. Immunofluorescence and CPE revealed that only pyrogen induced conversion from latency to activation and that the drug also enhanced virus production. Although prednisolone failed to induce activation, it did have an enhancing effect on slowly multiplying virus. Presumably, activation and enhancement of virus replication do not occur as the result of the same mechanism but the latter may be influenced by hormones. Microbial products may produce both effects separately or simultaneously.