Infection of thymus cells with a guinea pig herpes-like virus was studied in monolayer cultures, organ cultures, and experimental animals. 1) In monolayer cultures thymus fibroblast-like cells appeared to be less sensitive to GPHLV infection than kidney epithelial cells. 2) Animals inoculated intrathymically with the virus showed high titers of infectious virus in both thymus and spleen immediately after inoculation. The virus titer in the thymus gradually decreased, but the titer in the spleen increased after a 1-week lag period. 3) One week after i.p. inoculation of virus, a moderate amount of virus was found in the spleen, but only a very small amount was present in the thymus. Four to 5 weeks after infection, the virus titer in the thymus increased but was always slightly lower than that in the spleen. Administration of cortisone had little effect on virus yields and no effect on antibody titers. After cortisone treatment moderate atrophy was seen in the thymus but none was seen in the spleen. 4) A simplified submerged organ culture system was developed for thymus and spleen tissues. Although virus inclusions could not be found in sections of infected tissues, such inclusions were seen in infected tissue pieces maintained as organ cultures for 8 to 15 days. Specific GPHLV antibody in the organ culture medium inhibited the development of inclusions which, however, appeared when the antibody was removed.
This investigation was supported by United States Public Health Service Research Grant AI 08648 from the Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, and Veterans Administration Research Funds.
Address reprint requests to Dr. G. D. Hsiung, Virology Laboratory, Veterans Administration Hospital, West Haven, Connecticut 06516.