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CARCINOEMBRYONIC ANTIGEN 100 % PUR ERFA Biotech of Montreal, Canada, announces the availability of purified carcinoembryonic antigen (CEA) of the highest quality and batch consistency.
CEA is a fairly typical, high-molecular weight, cell surface glycoprotein. It consists of a single polypeptide chain and carbohydrates that constitute 50-60% of CEA molecule giving rise to an unusually high degree of molecular size heterogeneity. Antibodies induced against CEA would react with a variety of proteins present in normal tissues such as: non-specific cross-reacting antigen (NCA), NCA-II, biliary glycoprotein 1 (BGP-1), normal colon washing(NCW), and meconium antigen.
Initially it was hoped that the circulating CEA level would be both a sensitive and specific marker for the presence of cancer. These hopes have largely been dispelled as clinical evidence accumulated. Thus, CEA assay cannot be used for population screening or cancer diagnosis, as it become apparent that CEA not only circulates in small quantities in normal individuals, but is not always elevated in early stages of cancer. Despite these problems, the CEA assay has taken a definite place in the management of cancer patients, both preoperatively and postoperatively, in whom the diagnosis of cancer has already been established. Serial CEA determinations allow initiation of antitumor chemotherapy, radiotherapy, or "second look" surgery at an earlier stage of progression of disease, when the tumor loads are small and potentially curable. The immunoperoxidase staining of tumor tissue for CEA has proven to be a useful adjunct for pathologists. The degree of tissue CEA staining correlates well with plasma CEA levels, the degree of tumor differentiation, the stage of disease, the histologic tumor type, and the clinicla prognosis of various carcinomas. Of importance is the fact that CEA immunohistochemistry can be performed retrospectively on paraffin blocks allowing a direct comparison between the primary lesion and initially occult metastatic disease. CEA is not immunogenic in patients bearing CEA-producing tumors, however, tolerance to CEA could be broken by proper immunological manipulation. Liposomal carriers are able to potentiate immunological responsiveness against weakly immunogenic antigens. It is also possible to incorporate and retain CEA within the aqueous phase of liposomal carriers and that anti-CEA antibodies could be elicited in mice immunized with liposomal CEA. ANTIGÈNE CARCINOEMBRYONNAIRE 100 % PUR
ISOLATION AND PURIFICATION OF CEA ERFA's CEA has been purified under the most stringent conditions. The starting material for Erfa's CEA is the richest source of CEA known: hepatic metastases from colorectal cancers. Purification proceeds through water homogenization, perchloric acid extraction, ion-exchange, affinity and gel filtration chromatographies. PHYSICOCHEMICAL PROPERTIES
POTENTIAL APPLICATIONS (1) Structural and functional analyses of CEA molecule (2) Preparation of anti-CEA monoclonal antibodies (3) Preparation of anti-CEA heteroantisera (4) Standard curves for quantitative CEA assay (5) Cancer immunotherapy
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