ISOLATION OF TUMOR-ASSOCIATED PROTEIN FROM SERA OF COLON TUMOR-BEARING RATS USING POLYCLONAL ANTIBODIES ENTRAPPED IN GEL FIBERGLASS COLUMNS

A new, effective support for the isolation of proteins has been invent ed utilizing a gel fiberglass (GFG) (R. Zusman, Patent application 199 2, 1993). We describe the utilization of this support to isolate tumor -associated proteins (TAP) from sera of colon tumor-bearing rats. Sera were percolated through GFG columns with entrapped anti-rat colon can cer IgG from rabbits. TAP were eluted in a large amount, up to 3 mg/ml sera/column. Their affinity to antitumorous polyclonal antibodies was detected by ELISA. Western immunoblotting with commercial monoclonal antibodies has identified the isolated antigens as p21 and p53. Their concentrations were much higher (up to 1,000 times) in sera from tumor -bearing rats compared to control rats. The method was highly reproduc ible. It is suggested that data obtained can be considered as a basis for the further improving of quantitative methods of diagnosis.