Leukemia induction by Friend virus in normally leukemia virus resistant mice after treatment with methyl methane sulfonate

F1 offspring of virus-resistant C57B1/10 females and virus-sensitive SJL/J males are normally resistant to Friend leukemia virus. However, after treatment of these hybrids with methyl methane sulfonate (MMS), Friend leukemia virus given within 5 hrs of the treatment caused many individuals to succumb to erythroleukemia with characteristic elevated white counts, hepatometaly, splenomegaly, and high hematocrit. Although MMS was found immunosuppressive in these mice when given alone, it was found to enhance humoral immune function measured by a plaque forming assay against sheep red blood cells, when given in combination with the virus. These results suggest that MMS enhances viral leukemogenesis by some mechanism other than immunosuppression

Dna-dependent-dna-polymerase. Possible limiting influence on cell reproduction during viral leukemogenesis.

Evidence is presented that during viral leukemogenesis spleen cell nuclei show an increase in labelling index and mean grain count, that is not accompanied by any changes in the nuclear level of DNA-polymerase-alpha. It is suggested that polymerase production remains under the control of the normal cell mechanisms and the virus may affect cell proliferation by altering the primer-template levels