Expression of endogenous murine leukaemia viruses in AKR/J streaker mice

MICE of the AKR/J strain show high rates of spontaneous thymic lymphoma and are chronically infected with murine leukaemia viruses. Total thymectomy in young mice of this strain results in a marked decrease in the incidence of leukaemia. The finding of athymic mutant mice on the AKR/J background (referred to as streaker mice) is of importance in the study of genetic factors which influence virus expression and leukaemogenesis. Here we report that mice of both normal and mutant genotypes vary in the expression of a particular class of murine leukaemia virus. This lower virus expression in conjunction with the absence of a thymus leads to a lower tumour incidence in streaker mice.