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Radiation leukemia in C57BL/6 mice. II. Lack of ecotropic virus expression in the majority of lymphomas

Journal Article · · J. Exp. Med.; (United States)

The expression of endogenous ecotropic viruses in radiation-induced thymomas of C57BL/6 mice was examined. Competition radioimmunoassays for AKR MuLV were used for viral antigen expression. Three of 40 lymphomas had readily detectable ecotropic at levels of 95 to 689 ng/mg protein; the remainder of the tumors had no detectable (less than 1.0 ng/mg protein). Thirty thymomas were characterized by the presence of MuLV at levels of 1 to 10 ng/mg protein, levels that were comparable to those found in thymus extracts from age-matched, nonirradiated control. Ten tumors were characterized by having levels of 10 to 30 ng/mg protein. In one tumor significant levels of AKR MuLV were detectable. Since B-tropic and N-tropic viruses from C57BL/6 mice have glycoproteins indistinguishable from AKR MuLV and the N-tropic virus had a serologically identical to AKR MuLV, these results demonstrate that overt endogenous ecotropic virus expression is only rarely detectable in B-tropic virus was detectable in 2 of 40 thymomas and endogenous N-tropic virus was detectable in 1 of 40 thymomas. The lack of overt expression was also confirmed by cytotoxicity assays using monospecific antisera to these viral proteins. Radiation-induced lymphomas were also examined for the presence of reverse transcriptase after chromatography of tissue extracts on poly G-Sepharose. The results taken together demonstrate that overt endogenous ecotropic virus expression is only rarely detectable in radiation-induced thymomas of C57BL/6 mice.

Research Organization:
National Cancer Inst., Frederick, MD
OSTI ID:
7323804
Journal Information:
J. Exp. Med.; (United States), Journal Name: J. Exp. Med.; (United States) Vol. 144:6; ISSN JEMEA
Country of Publication:
United States
Language:
English