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C Wagener

Publications and source records attributed to C Wagener.

At least 109 records · Page 6Linked to original sources
PubMed1986

Transblot studies with biotin-labeled proteins: electrophoretic mobilities and detection limits.

Molecular weight standard proteins, mouse IgG as well as several antigens cross-reacting with the carcinoembryonic antigen (CEA), were biotin labeled, submitted to sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and transferred to nitrocellulose. The bound proteins were revealed by the use of avidin-peroxidase conjugates and a suitable substrate. The ratio of N-hydrosuccinimido biotin (NHSB) to protein yielding the lowest detection limit was determined. At an optimal NHSB/protein ratio, 0.33 ng of IgG heavy chains and 0.17 ng of IgG light chains could be visualized. With the exception of human albumin and ovalbumin, the increase in apparent molecular weight after biotin labeling was less than 10% for the proteins tested. The method has proven to be a valuable addition to Western blots performed with CEA-related antigens and monoclonal anti-CEA antibodies.

Animals↗
PubMed1985

Delineation of four carcinoembryonic antigen (CEA) related antigens in normal plasma by transblot studies using monoclonal anti-CEA antibodies with different epitope specificities.

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 greater than 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.

Antibodies, Monoclonal↗
PubMed1985

Monoclonal antibodies for carcinoembryonic antigen (CEA) as a model system: identification of two novel CEA-related antigens in meconium and colorectal carcinoma tissue by Western blots and differential immunoaffinity chromatography.

In a previous study, five monoclonal antibodies against the carcinoembryonic antigen (CEA) with different epitope specificities were delineated. One of these antibodies which exhibits a high affinity for CEA binds to different carcinoma tissues, to liver tissue, and to granulocytes. This antibody was selected for the immunoaffinity purification of CEA and related antigens from colorectal carcinoma tissue, from spleen tissues, from bile, and from meconium. After elution from the immunosorbent, the antigens were separated by SDS-PAGE, were transferred to nitrocellulose, and were incubated with the five different antibodies. Antibody T84.1 bound to the following antigens: 177 kD and 128 kD from colonic carcinoma, 81 kD from bile, 49 kD from spleen, as well as 165 kD and 100 kD from meconium. Two additional antibodies showed a similar binding pattern. The fourth antibody (CEA.11) bound to the 165 kD meconium antigen and to the two colorectal carcinoma antigens. The fifth antibody (T84.66) showed a strong reaction with the 177 kD colorectal carcinoma antigen and a faint reaction with a 183 kD antigen in meconium. As judged from m.w. and immunochemical properties, the 128 kD colorectal carcinoma antigen and the 100 kD meconium antigen are two novel CEA-related antigens. Because antibody CEA.11 did not bind to the 100 kD meconium antigen in Western blots, the 165 kD antigen could be eluted from a CEA.11 immunosorbent without contamination by the 100 kD antigen. Similarly, as predicted from the binding pattern in the Western blots, the two colorectal carcinoma antigens were separated from each other by a T84.66 immunosorbent.

Antibodies, Monoclonal↗
PubMed1984

Binding of five monoclonal anti-CEA antibodies with different epitope specificities to various carcinoma tissues.

Five monoclonal antibodies that recognize different epitopes on carcinoembryonic antigen (CEA) were reacted with tissue sections of various carcinoma specimens. The vital, non-necrotic tissues of those carcinomas of the oesophagus, pancreas, colon and rectum, medullary thyroid, ovary and cervix in which CEA related epitopes were detectable bound all five antibodies to a similar degree. In 3/5 lung carcinomas, 2/10 mammary carcinomas and 1/5 gastric carcinomas, a significantly different binding of the monoclonal antibodies by vital tumour tissue was present as determined by three independent investigators. In necrotic tissue areas, heterogeneity of antibody binding was more common. In a previous investigation, it was shown that normal granulocytes and liver tissue differentially bind the monoclonal anti-CEA antibodies, indicating the presence of crossreacting antigens. The equivalent binding of the five monoclonal anti-CEA antibodies to most of the carcinomas tested suggests that this binding is due to the presence of complete CEA molecules and not only of cross-reacting antigens.

Antibodies, Monoclonal↗
PubMed1984

Use of biotin-labeled monoclonal antibodies and avidin-peroxidase conjugates for the determination of epitope specificities in a solid-phase competitive enzyme immunoassay.

The epitope specificities of monoclonal antibodies against carcinoembryonic antigen (CEA) were determined in a solid-phase, biotin-avidin enzyme immunoassay. Constant amounts of biotin-labeled antibodies were incubated with the immobilized antigen in the presence of decreasing amounts of unlabeled antibodies. The biotinylated antibodies bound to the antigen were then reacted with avidin-peroxidase conjugates. The activity of the bound peroxidase was determined by the use of o-phenylenediamine and hydrogen peroxide.

Animals↗
PubMed1984

Diagnostic sensitivity, diagnostic specificity and predictive value of the determination of tumour markers.

The meaningful use of tumour markers for cancer diagnosis depends on the nature of the diagnostic problem, on an adequate definition of positive and negative test results, and on the correct choice of the patient group. Potential diagnostic applications lie in screening studies, diagnosis in patients with symptoms, staging and prognosis, diagnosis of local recurrence and distant metastases, and the monitoring of radio- and chemotherapy. In quantitative tests, a positive or negative test result may be obtained by the establishment of reference ranges in control groups, or by longitudinal studies in single patients. Usually, the monitoring of therapy and the diagnosis of tumour progression are performed by following the concentration pattern of the marker. When tumour marker determinations are performed in conjunction with other diagnostic tests, the diagnostic sensitivity or specificity may be increased, depending on the particular test combination. The determination of tumour markers with limited diagnostic specificity should be performed in groups of patients with a high prevalence of the disease, e.g. in the postoperative follow-up of patients with a high risk of tumour recurrence. Tumour markers with high diagnostic specificity are also useful in differential diagnosis.

Antigens, Neoplasm↗
PubMed1983

Localisation of carcinoembryonic antigen in embryonic and fetal human tissues.

Carcinoembryonic antigen (CEA) was localized in various embryonic and fetal human tissues between 8 and 16 weeks of gestation as well as in the colorectal mucosa of older fetuses, newborns and adults. Among the embryonic tissues, CEA was always present in the esophagus, the gastric antrum, the duodenum and the rectum. CEA positive staining of bile canaliculi of the liver was inconstant. All other embryonic tissues were CEA negative. During early fetal development, CEA positive staining of the esophagus, antrum and duodenum was inconstant. However, the whole colon became intensively stained. An inconstant CEA specific staining was found in parts of the midgut and in the bile canaliculi of the liver. The other organs remained CEA negative. Between the 17th week of gestation and birth, CEA staining pattern of the colorectal mucosa did not change. The staining intensity of late fetal colonic mucosa was similar to that of adult colonic mucosa.

Carcinoembryonic Antigen↗
PubMed1983

Monoclonal antibodies for carcinoembryonic antigen and related antigens as a model system: determination of affinities and specificities of monoclonal antibodies by using biotin-labeled antibodies and avidin as precipitating agent in a solution phase immunoassay.

A general method is described for the determination of affinity constants and antigen cross-reactivities of monoclonal antibodies. The method employs biotin-labeled antibody, radiolabeled antigen, and avidin as a precipitating agent in a homogeneous phase, competitive radioimmunoassay. This method eliminates incomplete or variable precipitation of antigen-antibody complexes often encountered in immunoassays in which monoclonal antibodies are employed. Using this assay system, we were able to rapidly determine the affinity constants for a number of monoclonal antibodies elicited to carcinoembryonic antigen (CEA). In the preceding paper it was shown that five of the monoclonal antibodies recognized distinct epitopes on CEA. In antigen-binding experiments with these five monoclonal antibodies, the percent of radiolabeled CEA bound in antibody excess ranged from 30 to 92%. The CEA cross-reacting antigens, normal cross-reacting antigen (NCA), and tumor-extracted, CEA-related antigen (TEX) were significantly bound by one, and to a lesser degree, by two of the five antibodies. Two antibodies did not bind significant amounts of NCA or TEX. In inhibition studies, the amount of unlabeled CEA leading to 50% inhibition of 125I-labeled CEA-binding was in the range of 3.7 to 760 ng per tube. The amount of TEX showing the same degree of inhibition was 23-fold greater than the amount of CEA for two antibodies and 351-fold greater than the amount of CEA for a third antibody. The affinity constants for CEA were in the range of 1.0 x 10(8) to 5.1 x 10(10) M-1. The affinity constants for NCA and TEX, determined for one of the antibodies, were three orders of magnitude lower in comparison to CEA. The heterogeneity of radiolabeled CEA as indicated by the low fraction bound by one of the monoclonal antibodies is shown to be most probably an artifact resulting from radioiodination damage. The application of the approach described in this report should eliminate the problems most commonly encountered in the determination of affinity constants for monoclonal antibodies or the use of monoclonal antibodies in competitive, homogeneous-phase immunoassays.

Animals↗
PubMed1983

Monoclonal antibodies for carcinoembryonic antigen and related antigens as a model system: a systematic approach for the determination of epitope specificities of monoclonal antibodies.

A systematic approach for the determination of epitope specificities of monoclonal antibodies to a complex antigen system is described. After initial screening to identify antigen-binding monoclonal antibodies, one or more of the clones are isolated by limiting dilution cloning, grown in ascites, and the resulting antibodies secreted into the ascitic fluid are affinity purified on Sepharose-bound protein A, radiolabeled, and cross-compared with antibodies from other clones by a solid-phase competitive immunoassay. In this work, BALB/c mice were immunized with either purified carcinoembryonic antigen (CEA) or the CEA-producing cell line HC 84S. Spleen cells were fused with the mouse myeloma cell line Sp2/0-Ag14. The supernatants from 25 hybrids showed a significant binding of 125I-CEA (greater than or equal to 15%). Nine hybrids were cloned, resulting in 33 different clones. The antibodies produced by the different cloned hybrids and the remaining uncloned hybrids recognized a total of five different epitopes on CEA. All of the epitopes reside on the protein moiety of the molecule as determined by antibody binding to deglycosylated CEA. The monoclonal antibodies with five different epitope specificities were reacted with tissue sections of normal and cancerous tissues and with peripheral blood smears. Each of the five monoclonal antibodies reacted with tissue sections from colonic, gastric, lung, and mammary carcinomas, as well as from a benign colonic polyp and a resection margin from a colonic carcinoma. Four monoclonals reacted with normal liver tissue. Granulocytes in peripheral blood smears bound three antibodies strongly and one antibody weakly, and one antibody was not bound. One monoclonal antibody that reacted with normal liver tissue was not bound by granulocytes. The ability of these five monoclonal antibodies to differentially detect three different CEA-related antigens in normal and malignant tissues may have clinical utility.

Animals↗
PubMed1982

Binding of carcinoembryonic antigen (CEA) to an anti-CEA immunosorbent in the presence of detergents.

The binding of [125I]CEA to an anti-CEA Sepharose-4B immunosorbent has been investigated in the presence of detergents. Non-ionic detergents (Triton-X-100, Lubrol PX and Tørgitol NPX) at concentrations of 5-40 milligrams did not inhibit the binding of [125I]CEA to the immunosorbent. Sodium deoxycholate decreased the binding from 98% (concentration of detergent 0.6 milligram) to 41% (concentration of detergent 20 milligrams). Sodium dodecyl sulfate inhibited the binding of [125I]CEA to the immunosorbent considerably, even at low concentrations.

Carcinoembryonic Antigen↗
PubMed1981

Immunohistochemical localisation of alpha-fetoprotein (AFP) in germ cell tumours: evidence for AFP production by tissues different from endodermal sinus tumour.

20 germ cell tumours have been studied with respect to the presence of alpha-fetoprotein (AFP), using the peroxidase-antiperoxidase (PAP) technique. 6 out of 20 tumours contained elements of endodermal sinus tumour (EST) and were AFP positive. 16 tumours were diagnosed either as pure embryonal carcinomas (6) or as mixed germ cell tumours, containing elements of embryonal carcinoma (10). In 3 of these 16 tumours AFP was localised definitely in the embryonal carcinoma cells; in an additional 6, AFP was also detected but it could not be decided whether AFP was present in embryonal carcinoma cells or in EST cells during early differentiation. In 2 of 7 immature teratomas, AFP was shown to be present in cylindric epithelia. All seminomas (4) studied were AFP-negative. These results show that AFP, which occurs regularly in EST, may also be present in embryonal carcinomas as well as in immature teratomas. Thus, it seems that the immunohistochemical demonstration of AFP by the PAP technique is a suitable method of identifying late stages of embryonal carcinoma or early stages of endodermal sinus tumour during the process of differentiation.

Dysgerminoma↗
PubMed1981

Localization and concentration of carcinoembryonic antigen (CEA) in gastrointestinal tumors: correlation with CEA levels in plasma.

In 50 patients with gastrointestinal carcinomas, the following tumor parameters were studied: the concentration and localization of carcinoembryonic antigen (CEA) in tissue, extension, invasion, infiltration, differentiation, and necrosis. CEA concentrations were measured in plasma samples of all patients. In 7 patients with gastric carcinomas, CEA concentrations in tissue were low. Generally, only single cells or cell groups were CEA-positive. Elevated CEA levels in plasma resulted mainly from distant metastases and not from the primary tumor. In 43 colorectal carcinomas, CEA concentrations in tissue varied between 1.5 and 472 microgram/g tissue. They were closely related to the degree of accumulation of CEA-positive necrotic material in the degree of accumulation of CEA-positive necrotic material in the neoplastic glands. In 35 patients with colorectal carcinomas without CEA producing distant metastases, preoperative CEA levels in plasma were normal when tumor necrosis and perineural invasion were absent and CEA concentrations in tissue were low. CEA levels in plasma were regularly elevated when the tumor showed considerable necrosis in the presence of high CEA concentrations in tissue.

Carcinoembryonic Antigen↗
PubMed1981

Immunohistochemical demonstration of carcinoembryonic antigen in normal, transitional and inflamed colonic mucosa.

Carcinoembryonic antigen (CEA) had been demonstrated immunocytochemically in normal colorectal mucosa (resection margins of colonic carcinomas), in transitional mucosa (mucosa adjacent to carcinomas), in non-specific proctitis and colitis, and in ulcerative colitis. In the resection margins and in non-specific proctitis and colitis, specific CEA staining is generally observed at the surface epithelium. In transitional mucosa, CEA staining is most intense in branching crypts and at the base of the crypts. In ulcerative colitis, areas with regenerative activity as well as precancerous or cancerous specimens exhibit an intense CEA positive membrane straining. In conclusion, colonic tissue with a high proliferative activity, such as transitional mucosa and ulcerative colitis, show a more intense CEA staining than normal colonic tissue. Moreover, the staining pattern is different in proliferating tissues as compared to normal tissue. A pronounced membrane staining in ulcerative colitis indicates rather a higher proliferative activity than cancer or precancer.

Carcinoembryonic Antigen↗
PubMed1980

[Second International Expert Meeting of the German Foundation for Cancer Research, "Current trends in cancer research." Critical review of tumour markers in diagnosis and surveillance].

The 2. International Expert Meeting of the "Deutsche Stiftung für Krebsforschung" on "Current Trends in Cancer Research", was held from May 11.-14., 1979, in Bonn. The conference dealt with a special subject: it was dedicated to the critical evaluation of tumor-marker substances with all their possible applications in clinical oncology. The aim was to reach clear conclusions about the real usefulness of tumor-markers in diagnosis and prognosis of cancer, as well as in the surveillance of already diagnosed patients. Moreover, the choice of the most appropriate tumor marker(s) for the different tumors out of the variety of the currently known substances, was to be cleared up. The sequel of the experts' critical considerations resulted in answer to three principle questions; these answers could serve as a basis for recommendations to all clinicians interested in oncology, who already are dealing with tumor-markers or intend to do so.

Carcinoembryonic Antigen↗