Purification of the Carcinoembryonic Antigen (CEA) with Immunoadsorbents (original) (raw)
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International Journal of Cancer, 1989
A series of 14 monoclonal anti-carcinoembryonic antigen (CEA, M, la0,OOO) antibodies (MAbs) that show a strong degree of selective reactivity for human colon carcinomas versus normal adult tissues were used to construct a serological map of the CEA molecule. The MAbs were generated using extracts of colon carcinomas as immunogen and are thus given a COL designation. None of the 14 COL-MAbs tested were reactive with purified non-specific cross-reacting antigen (NCA, M, 55,000) from normal lung, although some showed reactivity to human granulocytes. All the COL-MAbs tested were reactive with normal fecal antigen-2 (NFA-2, M, 170,000); however, many of the COL-MAbs demonstrated a higher affinity constant to CEA than to NFA-2. Crosscompetition radioimmunoassays classified the I 4 COL-MAbs into 5 groups. The chemical nature of the COL-binding domains was tested using chemically or enzymatically treated C E A all reacted with periodate-treated CEA and deglycosylated CEA, indicating that the COL-reactive epitopes appear to be of a proteinaceous nature. Heat treatment, reduction, alkylation, pepsin digestion or pronase treatment of CEA, however, gave differential results with respect to COL binding. Antibody titration experiments were carried out to define differential reactivities to colorectal carcinoma versus NCA-containing granulocyte extracts; these results were compared with results obtained using several anti-CEA MAbs that have been used in clinical trials. Granulocyte binding and biochemical studies showed that the COL MAbs may distinguish as many as 7 to 10 CEA epitopes.
International Journal of Cancer, 1973
A quantitative study of carcinoembryonic antigenic activity (CEA) in extracts of 44 tumors, 42 fetal and 36 non-malignant adult tissues from various organs was made and the CEA content detected by rnicroradioimmunoassay was related to the wet tissue weight. A variety of malignant neoplasms, including carcinomas, sarcoma and Hodgkin's disease, contained CEA (range 17 to 2727 ng) ; apart from gastrointestinal carcinomas which had the highest content of CEA (230-2727 nglg) only carcinomas of the lung contained moderate amounts of CEA (63-950 nglg). The amount of CEA in extracts of fetal and normal adult organs was mostly low or not detectable except in the gastrointestinal tract and pancreas where it ranged from 65 to 200 nglg in the fetus, and 28 to 86 nglg in the adult. Diflerences in mean content of CEA between normal and cirrhotic livers were not significant. Although our results indicated that CEA was present in varying amounts in a variety of tumors the identification of these reactive substances will require more precise physico-chemical and antigenic characterization.
Molecular Immunology, 1985
Antigens related to the carcinoembryonic antigen (CEA) were isolated from normal human plasma by perchloric acid extraction, gel permeation chromatography and immunoaffinity chromatography using a monoclonal antibody with broad specificity and high affinity. The antigens were separated by SDS-polyacrylamide gel electrophoresis and transferred to nitrocellulose. The binding of five monoclonal anti-CEA antibodies with different epitope specificities to the immobilized antigens was analyzed. Two antigens with mol. wts of > 200,000 and 177,000 bound all five antibodies, and two antigens with mol. wts of 114,000 and 85,000 bound three of the five antibodies. The findings reported indicate that even monoclonal antibodies with high specificity for colonic cancer CEA detect CEA-related antigens in normal human plasma.
Isolation of carcinoembryonic antigen by an improved procedure
Immunochemistry, 1978
An improved procedure for the isolation of carcinoembryonic antigen (CEA) has been developed.Lengthy dialysis. ultrafiltration and lyophilization steps following perchloric acidextraction are replaced by a simple ethanol precipitation of the CEA prior to the chromatographic purification steps. Chemical and immunochemical characterization of CEA prepared by this procedure showed no significant differences compared to CEA prepared by the more lengthy procedure not using ethanol precipitation.
Isolation from human gastric juice of an antigen closely related to the carcinoembryonic antigen
International Journal of Cancer, 1976
A carcinoembryonic antigen-like antigen (s) (CELIA) was isolated from normal human gastric juice by immunoadsorbents and gel chromatography. The isolated CELIA reacted identically to CEA in immunodiffusion tests against anti-CEA and anti-CELIA. Other experiments suggested subtle differences between CELIA and CEA. Two out of six CELIA preparations tested in immunodiffusion did not react in a completely identical manner with CEA. In gel filtration, CELIA eluted slightly after CEA. Absorption of anti-CEA with CELIA resulted in antisera with greatly reduced reactivity to CELIA, but retained anti-CEA activity. Such antisera may be helpful in attempts to increase the cancer specificity of the CEA test.
Proceedings of the National Academy of Sciences, 1983
A two-site monoclonal antibody-enzyme immunoassay (MEIA) for carcinoembryonic antigen (CEA) was developed that uses two monoclonal anti-CEA antibodies, which recognize two different epitopes in the peptide moiety of CEA. The assay was sensitive to 0.5 micrograms/liter and had a measuring range of 0.5-200 micrograms of CEA per liter. It was highly specific inasmuch as none of three known CEA-related substances, "nonspecific crossreacting antigens 1 and 2" (NCA-1 and NCA-2) and biliary glycoprotein I (BGP I), reacted in the assay. NCA-2 (meconium antigen) is very similar to CEA. None of five commercially available CEA assays were able to differentiate between CEA and NCA-2. With one exception (colon), normal tissue extracts did not react in the MEIA even when tested at very high concentrations. Sera from a total of 180 healthy individuals and patients with malignant and nonmalignant disease were analyzed for CEA levels by using the MEIA and in parallel a conventional radioim...