[The isolation of anti-carcinoembryonic antigen (CEA) immunoglobulins and their use in immunocytochemical and immunoenzyme (ELISA) technics].

Abstract

Carcinoembryonic anti-antigen (CEA) polyclonal antibodies were obtained in ram and rabbit using as antigen source the extracts with perchloric acid from the human colon adenocarcinomas. CEA was purified by gel filtration on Sepharose 4BCL and ion-exchange chromatography (DEAE-Sephadex A50). The total antiserum was absorbed with human serum and perchloric acid extract from the normal colon. IgG anti-CEA was purified by chromatography of the monospecific antiserum, then tested for bonding specificity, at cryostat on sections of colon adenocarcinoma, by indirect immunoperoxidase. The specific reaction was compared with that obtained by the same technique, using two monoclonal antibodies specific to the CEA molecule (MAb-26/3/13 and MAb-26/5/1 respectively). IgG anti-CEA was also used for obtaining some IgG-peroxidase conjugates, with an immunoenzymatic system, ELISA type, with two antibodies according to the model of the ELISA kits produced by the Cantacuzino Institute (ELISA-AFP). The ELISA-CEA kit was standardized using an international CEA standard. CEA was quantitatively determined with this immunoenzymatic system (ELISA-CEA) on a group of 15 healthy subjects (average: 4.8 +/- 0.12 ng/ml) and on 30 patients with colorectal tumours (average: 26.6 +/- 0.15 ng/ml). ELISA-CEA kit, sensitive and reproducible, allow the usual quantitative determination of CEA, a useful marker in diagnosing and monitoring tumour evolution.