Lack of Thy 1.2 antigen expression on the surfaces of mouse mammary epithelial cells.

Monoclonal antisera against mouse Thy 1.2 antigen were used to assess the expression of Thy 1.2 antigen on BALB/c and BALB/cfC3H normal mouse mammary gland epithelial cells (MMEC) and on spontaneous and transplanted BALB/cfC3H mammary adenocarcinoma cells. Immunofluorescence (IF) assays with the monoclonal anti-Thy 1.2 sera demonstrated that Thy 1.2 antigen was not expressed on the surface membranes of MMEC (both virus-free BALB/c and virus-infected BALB/cfC3H) and tumor (BALB/cfC3H) mammary epithelial cells. A specific antiserum against MMEC was used to establish the expression of this normal antigen(s) on the surfaces of both MMEC and tumor mammary epithelial cells obtained from virus-free and virus-infected mice. In addition, the expression of the mammary tumor virus envelope glycoprotein gp52 was determined by indirect IF on the surfaces of virus-infected mammary epithelial cells, both MMEC and tumor cells.