Development and use of a quantitative immunoassay for the calcium-binding protein (molecular weight, 11,500) of Morris hepatoma 5123.

An antiserum has been developed against a M.W. 11,500 calcium-binding protein purified to homogeneity from Morris hepatoma 5123tc. The antiserum was specific and did not cross-react with an excess of two other calcium-binding proteins, calmodulin or parvalbumin. The amount of the tumor protein has been quantitated immunologically in several Morris hepatomas, early neoplastic liver nodules, and mouse sarcomas. This protein could not be detected in any normal rat tissue. The calcium-binding protein in mouse tumors appeared similar to that in rats by both crossed polyacrylamide gel electrophoresis-immunoelectrophoresis and crossed isoelectric focusing immunoelectrophoresis.