HUMAN CARCINOEMBRYONIC ANTIGEN

摘要

PURPOSE:To obtain a gene to code an amino acid sequence containing a specific antigenic part of human carcinoembryonic antigen (human CEA) protein to make it possible to prepare an antigen to react only with human CEA but not with CEA-related antigen. CONSTITUTION:A cDNA library is prepared by using mRNA extracted from tissue cell of cancerous patient, preferably from intestinum crassum tissue of colon cancer patient. A clone to develop human CEA protein is screened from cDNA library by the use of an existing CEA antibody and phage DNA is separated from a positive clone. Whether the aimed cDNA of human CEA is inserted into the phage DNA is ascertained by restriction enzyme analysis and base sequence of the inserted cDNA is determined. By using fragment of the prepared CEA gene, a specific antigen peptide from which an unnecessary peptide range such as a peptide common to the CEA-related antigen is removed can be produced by a microbial or animal cell.