A COLORIMETRIC IMMUNOASSAY FOR THE DETECTION OF E-CADHERIN AND CALCINOEMBRYONIC ANTIGEN (CEA) EXPRESSION ON HUMAN COLON-CARCINOMA CELL-LINES IN-VITRO

An immunohistochemical assay, using 96-well microtiter plates and base d on the avidin-biotin peroxidase reaction, was developed for the quan titation of E-cadherin and CEA expression on HT-29 and SW620 colon car cinoma cells. The optical density of the generated dye was measured af ter solubilization with alkaline SDS solution. The staining procedure was evaluated with respect to reproducibility (coefficient of variatio n and intra-class correlation coefficient). On HT-29 cells the level o f agreement for both E-cadherin and CEA were substantial, on SW620 cel ls almost perfect. The method allows testing compounds for their diffe rentiation inducing capacity in screening programmes on the basis of p rotein marker expression.