Virus expression in various tissues of mice inoculated with variants of gross leukemia virus

Abstract

Evolution of virus expression in various lymphoid tissues of C 3H/Fe mice, inoculated with 2 variants of tissue culture adapted Gross Passage-A virus, was studied with the aid of parallel in vitro XC co-culture technique and electron microscopic examination. When the mice were neonatally inoculated with a highly leukemogenic variant (TGV virus), 3 phases of virus expression could be distinguished during the average 2 months of latent period. In the early phase (for the first 3 weeks after virus inoculation) as well as in the later phase (after the 50th day), the virus could be detected abundantly in bone marrows and spleens, moderately in thymuses and slightly or not at all in lymph nodes and kidneys. In the intermediate phase (the 20th to the 50th days), the virus disappeared completely or decreased significantly from all tissues tested. In the case of mice similarly inoculated with a non-leukemogenic variant (N 1 virus), no virus could be detected in all tissues during the 2 months period after virus inoculation. The virus recovered from in vitro explanted and cultured kidney cells, taken from mice inoculated neonatally with TGV virus, induced typical Gross type lymphoid leukemia in all C 3HeB/Fe mice inoculated as newborns. However, in vitro cellular tropism of this virus was revealed as B tropic while that of the original TGV virus was N tropic. Frequent differentiation to heterologous tissues was observed by electron microscope in the thymuses of mice inoculated as newborns with TGV virus.