Monoclonal antibodies identify a cea crossreacting antigen of 95 kD (NCA‐95) distinct in antigenicity and tissue distribution from the previously described NCA of 55 kD
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During the selection of monoclonal antibodies (MAb) raised against purified carcinoembryonic antigen (CEA), two MAbs were identified which immunoprecipitated a glycoprotein of 95 kD present both in perchloric acid extracts of normal lung and on the surface of normal granulocytes. This antigen was distinct from the previously reported normal glycoprotein crossreacting with CEA (NCA) which had a molecular weight of 55 kD. The difference between the smaller and the larger crossreacting antigens termed NCA-55 and NCA-95, respectively, was demonstrated by SDS-polyacrylamide gel electrophoresis, by elution from Sephadex-G200 and by selective binding to a series of anti-CEA MAb. Out of six MAb which all bound CEA purified from colon carcinoma, three did not react with these two crossreacting antigens, one bound only NCA-95, one reacted only with NCA-55 and one reacted with both NCA-55 and NCA-95. Immunoadsorbent purified preparations of 125I labelled NCA-95 and NCA-55 were found useful for the screening of new anti-CEA MAb. In addition, when tested on frozen sections of colon carcinoma, normal spleen, normal lung and pancreas, each type of MAb gave a clearly different pattern of reactivity. The three anti-CEA MAb which did not bind any of the crossreacting antigens stained only the colon carcinoma cells; the MAb binding to either one of the two types of NCA gave a similar pattern of reactivity both on colon carcinoma cells and on granulocytes. However, on normal lung and pancreas, the MAb binding NCA-55 stained granulocytes as well as bronchiolar and alveolar epithelial cells in lung and inter- and intra-lobular duct epithelial cells in pancreas, whereas the MAb binding only NCA-95 stained only the granulocytes. Thus, the newly identified NCA-95 appears to differ from NCA-55 not only in terms of molecular size and antigenicity but also by the fact that in normal lung and pancreas it is found in granulocytes but not in epithelial cells.Keywords:
Carcinoembryonic antigen
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Antigenicity
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Abstract The effect of heat treatment on the antigenicity of α-lactalbumin (α-LA) and β-lactoglobulin (β-LG) in whey protein isolate (WPI) was investigated at temperatures in the range of 50–120°C for times from 0.5 to 30 min. The antigenicity was determined by an indirect competitive enzyme-linked immunosorbent assay. The heat denaturation of α-LA and β-LG was revealed by SDS-PAGE electrophoresis. The antigenicity of α-LA and β-LG increased with increasing temperature from 50 to 90°C and the highest antigenicity of α-LA and β-LG was detected at 90°C. However, above 90°C the antigenicity of both proteins showed a remarkable decrease. When treated at 120°C for 20 min, the antigenicity of α-LA decreased below the initial value of the untreated sample. The antigenicity of α-LA and β-LG in WPI can be decreased at certain heat temperature and time.
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Whey protein isolate
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Abstract The effect of weight ratio of protein to sugar (0.17–7.83), temperature (40–60°C) and time (24–120 h) on the antigenicity of β-lactoglobulin (β-LG) in conjugates of whey protein isolate (WPI) with glucose was investigated. Response surface methodology was used to carry out an optimisation of the reaction conditions leading to the minimum antigenicity of β-LG. Conjugation of WPI with glucose could reduce effectively the antigenicity of β-LG. This reduction of antigenicity could be controlled by regulating three independent variables (weight ratio of WPI to glucose, temperature and time). The model for optimal reaction conditions of a lower antigenicity of β-LG was established. Weight ratio of WPI to glucose had the greatest effect on the antigenicity of β-LG. Reaction time influenced the antigenicity of β-LG to a lesser extent.
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Whey protein isolate
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Two monoclonal antibodies, 918(4) and 139(7), directed against either bovine or porcine pepsin, respectively, were retained among 365 positive hybridoma clones. These monoclonal antibodies were characterized by using both indirect and sandwich ELISA. Characterization of these monoclonal antibodies was further performed by the biospecific interaction analysis (BIA-core analysis). Then, they were used as antigenic probes to study the changes in antigenicity of both bovine and porcine pepsins induced by pH. The results demonstrated the importance of the conformational change in both catalytic activities and antigenic determinant accessibility of bovine and porcine pepsins. Furthermore, our results suggest that changes in the conformation due to pH can be detected by specific monoclonal antibodies.
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Pepsin
Hybridoma technology
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Summary If the tetanal flocculative reaction is carried out in the described manner, flocculating toxins show the average ratio of Lf:L+ as 1:10. The MLD values of tetanal toxins do not parallel the antigenicity of the tetanal toxoids prepared therefrom. Combining power values (L+ or Lf) of tetanal toxins cannot always be used for evaluation of antigenicity of the corresponding toxoids. For certain toxins prepared under defined conditions, however, a parallelism exists. The most reliable method of determining the antigenicity of tetanal toxoid is by means of an antigenicity test carried out in guinea-pigs or in mice.2
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Toxoid
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To reduce the antigenicity of egg white (EW), EW was treated with several proteolytic enzymes, trifluoromethanesulfonic acid (TFMS), heat, and NaOH. Competitive indirect enzyme-linked immunosorbent assay (ciELISA), using rabbit anti-EW antibody, was performed to examine the antigenicity of the treated EW's. Enzymatic hydrolysis gave no good effect on the reduction of the antigenicity of EW. Neither did the pretreatment with before the hydrolysis reduce the antigenicity. TFMS treatment removed the antigenicity of EW. The antigenicity of EW heated at for 30 min or treated with NaOH at 0.3% (w/v) and more, decreased to less than 1/10,000 as compared with that of native EW. The combinatory treatment with NaOH, followed by heat at for 15 min had a synergic effect on the reduction of the antigenicity of EW.
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The aim of this study was to evaluate the serum carcinoembryonic antigen levels in the diagnosis and in monitoring colorectal cancer patients at different Dukes' stage. Carcinoembryonic antigen serum levels were measured by Elisa using Sorine Biomedica kit (normal value: 5 ng/ml) in 240 colorectal adenocarcinoma. In the diagnosis, carcinoembryonic antigen levels were measured in 109 patients, in 42% of them, the carcinoembryonic antigen levels were elevated. The carcinoembryonic antigen levels were also evaluated in 309 serum from treated colorectal cancer patients. Fifty-nine percent of the serum of the patients with recurrence disease had elevated carcinoembryonic antigen levels and 41% of the serum of patients without recurrence also have elevated serum carcinoembryonic antigen levels. Ninety percent of the serum from treated patients without recurrence have normal serum carcinoembryonic antigen levels. We concluded that the sensitivity of carcinoembryonic antigen is lower in the diagnosis as described in others studies, mostly in patients with better prognosis. In the monitoring, patients with normal serum carcinoembryonic antigen levels, probably have no recurrence of the disease. In the other hand, patients with elevated serum carcinoembryonic antigen levels can have or not relapsed disease.
Carcinoembryonic antigen
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Monoclonal antibodies were generated against rat uterine estrogen-induced protein — creatine kinase (CK-EIP)— and two (MAb-28 and MAb-78) were studied. These antibodies were IgM but differed in their complementary antigenic determinants both of which were detectable on denatured but not on native CK-EIP. MAb-28 reacted with other CK-BBs but not with CK-MMs whereas MAb-78 reacted with both types of CKs. A measurement of antigenicity with the monoclonal antibodies under calibrated conditions showed differences among the CKs, notably between CK-BB from rat brain and CK-EIP when both were probed with MAb-28. The antigenicity of CK-BB (rat brain) was significantly lower than that of CK-EIP, indicating that the former either expresses less copies of the determinant recognized by MAb-28 than CK-EIP does, or possesses a determinant which interacts with the antibody with lower affinity. The monoclonal antibodies should help elucidate structure-function relationships in CK-BB and CK-EIP molecules, their anatomic distribution and their physiologic, pathologic and experimental variations in relation to gene expression induced by sex hormones.
Creatine kinase
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