This research will be directed toward evaluating differences in cell surface glycoproteins between metastasizing and nonmetastasizing tumors of the same line, determining the types and amounts of glycoproteins released from the cell surface, evaluating the immunogenicity of the released materials, and their ability to block the immune response of the host and correlating these observations with histopathological evaluation of the establishment and progression of metastasis. Two different rat mammary tumors will be studied (13762 and R3230 AC). Glycoprotein components will be analyzed by chemical and enzymatic membrane and surface labeling methods and by electrophoresis. Antibodies will be produced in rabbits by injection of whole tumor cells, isolated membranes or purified glycoproteins and purified by absorption, ion exchange and affinity chromatography. Glycoprotein material released will be identified and quantified by radioactive precursor labeling and immune precipitation, followed by counting and detergent electrophoresis. Tumor associated antigens and sialoglycoproteins will be analyzed in this manner. Release of the putative surface enzymes 5'-nucleotidase and nucleotide pyrophosphatase will be measured by their activities. Evaluation of the immunogenicity of released materials in the host animal will be evaluated from complement-dependent cytotoxicity, immune precipitation and indirect fluorescence studies on sera from normal animals injected with released materials. The immune response of the host will be evaluated from lymphocyte cytotoxicity, serum blocking and complement-dependent cytotoxicity studies. Efforts will be made to correlate chemical and immunological data with histopathological studies on the tumor-bearing animals.