Detection by Immunodiffusion of Mouse Mammary Tumor Virus in Milk Samples and Correlation with Tumor Development¹ Free

Milk from female mice infected with the mammary tumor virus (MTV) was examined in immunodiffusion for MTV virion antigen. Very few of the milk samples from females in the first lactation contained detectable virus; the incidence of positive samples increased in succeeding lactations. No correlation was observed between the early development of a mammary tumor and the presence of detectable amounts of MTV virion antigen in the milk of the first and second lactations. However, the presence of detectable MTV in the later lactations was correlated with the development of a mammary tumor during the experimental period.