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Biomedical subjects

E Engvall

Publications and source records attributed to E Engvall.

161 records · Page 9Linked to original sources
PubMed1976

Isolation from human gastric juice of an antigen closely related to the carcinoembryonic antigen.

A carcinoembryonic antigen-like antigen(s) (CELIA) was isolated from normal human gastric jucie by immunoadsorbents and gel chromatography. The isolated CELIA reacted identically to CEA in immunodiffusion testa 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.

Antigens↗
PubMed1976

Monkey antisera with increased specificity to carcino-embryonic antigen (CEA).

Three Macaca irus monkeys were immunized with purified human CEA. One received unmodified CEA and two were immunized with haptenated (4-hydroxy-5-iodo-3-nitrophenyl acetyl) CEA. All three monkeys formed precipitating antibodies to CEA. The antisera did not precipitate the CEA-related normal glycoprotein antigen (NCA). In contrast, CEA-immunized rabbits, sheep and goats invariably form antibodies against NCA. Radio-immunoassays showed the monkey antisera to contain trace amounts of antibodies to NCA but the titers were about 10-1,000 times lower than those in rabbit and sheep sera with comparable anti-CEA titers. These results show that monkeys produce antibodies against CEA, but respond weakly to a normal, CEA-related antigen. The weak response to NCA suggests that monkeys may possess an NCA-related antigen. Antisera lacking reactivity to normal CEA-related antigens may be helpful in establishing a more specific diagnostic test for CEA.

Animals↗
PubMed1976

A monkey antigen crossreacting with carcinoembryonic antigen, CEA.

Normal monkey tissues were found to contain an antigen which crossreacts immunologically with the carcinoembryonic antigen (CEA) of the human digestive tract. The monkey antigen reacted with complete or partial identity to the normal crossreacting antigen (NCA) in humans when tested in immunodiffusion against anti-CEA or anti-NCA. Extracts of monkey tissues inhibited in radioimmunoassays measuring human NCA. It is possible that monkey foetuses and colonic tumours contain CEA.

Animals↗
PubMed1976

Immunological crossreaction between alpha-fetoprotein and albumin.

Alpha-fetoprotein (AFP), a fetal protein associated with certain tumors, and serum albumin did not corssreact immunologically in native form. Unfolding of their polypeptide chains by reduction of the disulfide bonds followed by carboxamidomethylation produced derivatives with immunochemical properties different from those of the native proteins. Precipitating reactions and radioimmunoassays preformed with antibodies to such unfolded derivatives showed strong crossreactions between albumin and AFP. These assays were found to lack species specificity: AFPs and albumins from different species were equally active. Several other proteins unrelated to AFP or albumin did not react or reacted much less in these assays. These results support the conclusions derived from recent sequence data that AFP and albumin are structurally related and have a common ancestral gene.

Alkylation↗
PubMed1975

New serological test for malaria antibodies.

In an enzyme-linked immunosorbent assay test for malaria antibodies, antibodies to Plasmodium vivax and P. falciparum in man are detected using a crude antigen prepared from the simian malaria parasite P. knowlesi. The test may be suitable for epidemiological studies.

Adsorption↗
PubMed1975

Nature of the tumor-associated determinant(s) of carcinoembryonic antigen.

The carbohydrate moiety of carcinoembryonic antigen could be sequentially degraded by repeated cycles of periodate oxidation, reduction, and mild acid hydrolysis (Smith degradation). After three complete degradations, all fucose and sialic acid, 80% of the galactose, 65% of the mannose, and about 40% of the N-acetylglucosamine were eliminated without impairing the ability of degraded carcinoembryonic antigen to react with specific antisera against the antigen. Inhibition studies in a carcinoembryonic antigen/rabbit anti-carcinoembryonic antigen precipitating system with oligosaccharides covering previously known internal structures of glycoproteins and presumably corresponding to the internal carbohydrate region of the antigen, demonstrated that none of the compounds tested was inhibitory. Nor could any inhibitory effect on the binding of carcinoembryonic antigen to antibody against the antigen in a radioimmunoassay system be domonstrated for the carbohydrate moiety prepared by hydrazinolysis or the glyco peptide fraction isolated after papain degradation of the antigen. However, if carcinoembryonic antigen is completely reduced and alkylated, with three intrachain disulfide bonds cleaved per 10-5 g, the immunological activity is reduced to 3-5% of untreated antigen. Furthermore, treatment of the antigen with 0.5 NaOH at 20 degrees for 2 hr completely abolished its ability to react with antiserum, whereas its ability to precipitate with a series of lectins was unchanged. No release of low-molecular-weight carbohydrate orchange in sugar composition of alkali-treated antigen was observed. Our tentative conclusion is that the carbohydrate moiety of carcinoembryonic antigen does not contain the tumor-associated determinant(s).

Acetylgalactosamine↗
PubMed1974

A microplate method of enzyme-linked immunosorbent assay and its application to malaria.

A microplate method of enzyme-linked immunosorbent assay is described. This method, which may be of value in the measurement of antibodies in various infectious diseases, is simple, cheap, and easy to carry out on a large scale. For field use, results can be assessed subjectively. The potential of the test is illustrated by a small seroepidemiological study of malaria.

4-Nitrophenylphosphatase↗
PubMed1971

Enzyme-linked immunosorbent assay. II. Quantitative assay of protein antigen, immunoglobulin G, by means of enzyme-labelled antigen and antibody-coated tubes.

Alkaline phosphatase from calf intestinal mucosa has been conjugated to a protein antigen, rabbit IgG. Such conjugates, prepared by glutardialdehyde, have been used in a competitive solid phase immunoassay. In this test native antigen inhibits the binding of the conjugate to homologous antibodies adsorbed to plastic tubes. Using this assay 1-100 ng/ml of the antigen could be determined.

Adsorption↗
PubMedDate not supplied

Muscular dystrophy in female dogs.

The most common form of muscular dystrophy in dogs and humans is caused by mutations in the dystrophin gene. The dystrophin gene is located on the X chromosome, and, therefore, disease-causing mutations in dystrophin occur most often in males. Therefore, females with dystrophin deficiency or other forms of muscular dystrophy may be undiagnosed or misdiagnosed. Immunohistochemistry was used to analyze dystrophin and a number of other muscle proteins associated with muscular dystrophy in humans, including sarcoglycans and laminin alpha2, in muscle biopsy specimens from 5 female dogs with pathologic changes consistent with muscular dystrophy. The female dogs were presented with a variety of clinical signs including generalized weakness, muscle wasting, tremors, exercise intolerance, gait abnormalities, and limb deformity. Serum creatine kinase activity was variably high. One dog had no detectable dystrophin in the muscle; another was mosaic, with some fibers normal and others partly dystrophin-deficient. A 3rd dog had normal dystrophin but no detectable laminin alpha2. Two dogs could not be classified. This study demonstrates the occurrence of dystrophin- and laminin alpha2-associated muscular dystrophy and the difficulty in clinical diagnosis of these disorders in female dogs.

Animals↗
PubMedDate not supplied

[The identification and partial characterization of merosin--a new specific protein of the basement membranes of certain tissues].

A tissue-specific basement membrane-associated protein has been identified by the use of monoclonal antibodies prepared against a protein fraction of human placenta. In frozen sections of human tissues the monoclonal antibodies decorated basement membranes of Schwann cells, striated muscle, and trophoblast. In antibody-affinity chromatography of limited pepsin digests of human placenta, a 65-kDa polypeptide was bound by the monoclonal antibodies. Polyclonal antisera and new monoclonal antibodies were raised against the isolated 65-kDa polypeptide, and they stained human tissues identically to the original monoclonal antibodies. An 80-kDa polypeptide was detected by these antibodies in placental extracts prepared without proteolysis. The 65-kDa and 80-kDa polypeptides were immunologically distinct from laminin, type IV collagen, fibronectin and major serum proteins. These polypeptides are presumably derived from a novel basement membrane-associated protein which we named merosin. Several cDNA clones were isolated which code for a protein specifically recognized by polyclonal antibodies to the 65-kDa fragment. In developing mouse tissues, merosin was first detected at the newborn stage. The restricted tissue distribution and the late development appearance of merosin suggest that the protein has a tissue-specific function in highly differentiated cells.

Animals↗
PubMedDate not supplied

CEA and CEA-like activity in gastric cancer.

CEA activity was studied using a three-layer bridge immunoperoxidase method in paraffin-embedded histological sections of gastric mucosa from patients with gastric cancer and from normal asymptomatic subjects. In all cases gastric cancer cells showed CEA or CEA-like activity irrespective of the histological type of cancer. The activity was located mainly in cellular membranes, on the brush border or in apical parts of the cell cytoplasm. CEA activity could not be demonstrated in mucosa specimens from normal controls. These results indicate that the appearance of CEA or CEA-like substances is regularly associated with the malignant transformation of epithelial cells of the gastric mucosa.

Adenocarcinoma↗