[Preparation and characterization of human colon tumor-associated antigen and its clinical significance].

To purify the colon tumor-associated antigen from cultured colon tumor cells, and to investigate its expression in the sera of patients with colon cancer.The monoclonal antibody (mAb) against human colon tumor-associated antigen 4D10 was employed as the ligand for the immunoaffinity chromatography to purify the colon tumor-associated antigen from the lysate of colorectal tumor cell LOVO. The purified antigen was identified by SDS-PAGE and Western blot. The expression of colon tumor-associated antigen in the sera of patients with colon cancer and in normal sera was detected by Sandwich ELISA.The purified colon tumor-associated antigen binding to mAb 4D10 was a heterodimer composed of two subunits with relative molecular mass M(r) of 30 x 10(3) and 35 x 10(3) respectively. The antigen was significantly higher expressed in sera from patients with colon cancer than that in normal sera (P<0.01).The tumor-associated antigen obtained from the colon tumor cells has been successfully purified through immunoaffinity chromatography with mAb 4D10, which may be useful for diagnosis on clinic.