[Study of the integral antigen of the membranes of fatty globules of human milk].

The glycoprotein with the molecular weight of 82,500 D (Ag3) was extracted from the native membranes of fatty globules of human milk and was purified by isoelectrofocusing. Polyclonal antisera (PCA) as well as monoclonal antibodies (MoAb)-ICO-21, ICO-22, ICO-26, ICO-29 against this membrane antigen were produced. The localization of the antigen in the human normal and malignant tissues was tested by the immunochemical technique. Apical staining of the Ag3 was in the acinus and duct cells of the normal breast. Weak staining with the antibodies to Ag3 was revealed in the epithelium cells of ovaries, bronchi, kidney tubules and uterine tubes. The far more pronounced staining of the Ag3 with PCA and MCA was observed in the cell cytoplasma both in the primary and metastatic breast and ovarian tumours. The specificity of the MoAb to Ags suggests that they will be useful in the diagnosis of the malignant disease of the breast and ovary.