Lymphocyte transformation in vitro to RII mouse milk antigen among woman with breast disease.

The cell-mediated immune responses of 110 women with benign or malignant breast disease were tested in in vitro lymphocyte transformation assay with an antigen preparation made from RIII mouse milk containing mammary tumor virus. About 50% of patients responded positively to the milk preparation. In contrast, 25% of normal women or women with other gynecological malignancies responded positively to the antigen (P = 0.015). The data demonstrate a similar response pattern among women with malignant or benign breast disease. In addition, a subpopulation of normal women with positive response to this antigen is clearly defined.