Further investigations of the biosynthesis of the major glycoprotein epiglycanin, at the surface of the nonstrain-specific TA3-Ha murine mammary carcinoma ascites cell of the strain A mouse will be performed. The relationship between ultrastructural features of the cell surfaces, the presence of epiglycanin, and the property of allotransplantability in nonstrain-specific ascites sublines of the TA3 tumor will be investigated. Chemical, immunochemical, and physical properties of epiglycanin will be investigated in order to gain a better understanding of structure-function relationships in masking of surface antigens in the TA3 tumor system.