Characterization of differentiation antigens of the mouse mammary epithelial cell (MME antigens) carried on the mouse milk fat globule.

The characterization of mouse mammary epithelial (MME) antigens from the mouse milk fat globule (MMFG) is described. Heterologous antisera against fat-free MMFG material identifies by indirect immunofluorescence techniques, cell-type-specific MME antigens on the surface of mouse mammary epithelial cells and MMFGs and not on cells of other tissues. Mammary epithelial cells of all mouse strains tested were positive. However, the intensity of staining differed. Specificity of anti-MME for MME antigens is demonstrated by competition and cross-absorption experiments. The MMFG is composed of 5 main proteinaceous components, 3 of which contain carbohydrate and which are shown to contain the specific MME antigens.