Cytological basis for enhancement of radiation-induced mortality by Friend leukaemia virus infection

Purpose: To analyse the cytological basis for enhancement of radiation‐induced mortality by Friend leukaemia virus infection.Materials and methods: Cellularity in haematopoietic tissues of C3H mice infected with FLV and/or whole‐body irradiation was examined.Results: When mice were treated with a sublethal dose (3 Gy) of irradiation at 1 week after virus infection, most manifested a severe loss of cellularity in the spleen, bone marrow and peripheral blood 2 weeks after irradiation. More than 90% of the mice died within 1 month post‐irradiation. However, this deleterious effect of virus infection on the survival of irradiated mice was observed only when they were irradiated at around 1 week after virus inoculation. Strain differences in the sensitivity to this effect were observed among virus‐sensitive strains of mice.Conclusions: The results indicate that Friend leukaemia virus infection can cause enhancement of radiation sensitivity of haematopoietic cells in host animals in a restricted manner in terms...