The influence of sex upon the development of friend virus leukaemia

The morbidity and mortality in Parkes mice of both sexes following the injection of various doses of Friend leukaemia virus have been studied. Individual mice were tested for the presence of viraemia and for neutralizing and tumour‐specific cytotoxic antibodies. The principal findings were: (1) more rapid death among the female than the male mice; (2) the fact that, among the mice with splenomegaly, those with viraemia are usually male while those with neutralizing or cytotoxic antibodies are usually female; (3) the presence of circulating cytotoxic antibody in many mice with splenomegaly. It is hypothesized that female mice with Friend virus leukaemia are considerably superior to males in antibody‐producing capacity and that the former owe their more rapid death to tissue damage caused by an immunological response to the virus or cellular neo‐antigen.