Cell line-specific cell surface components of hypotetraploid ascites mammary carcinoma cells inducing humoral reactions in the syngeneic host.

Cell-line specific cell surface components were demonstrated on cells of various hypotetraploid ascites cell lines, but not on hyperdiploid cells derived from a mammary carcinoma induced by mammary tumor virus (MTV) in syngeneic C3H/He mice. These substances caused cell-line-specific transplantation antigenicity and were identified, together with MTV-associated substances and tumor-associatied embryonic materials, as being the binding sites for tumor cell agglutinating factors found in sera from tumor-bearing and regressor animals. Particles containing the cell line-specific substances were released from these cells by hypnotic treatment. They could be purified as a single peak in a sucrose density gradient. They were, however, not dissociated from the MTV-associated substances. Absorption studies of agglutination activity were extensively used for demonstration of specificity.