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T Feizi

Publications and source records attributed to T Feizi.

At least 181 records · Page 10Linked to original sources
PubMed1982

Antigenicities of mucins - their relevance to tumour associated and stage specific embryonic antigens.

It can now be envisaged that there exists a distinct set of differentiation antigens formed by linear (i type) or branched (I-type) oligosaccharides and their fucosylated (and perhaps sialylated) derivatives. Several of these antigens are expressed in secreted glycoproteins (mucins) which are relatively abundantly available. Thus mucins can serve as valuable sources of oligosaccharide haptens of differentiation antigens just as they have done in the past with the major blood group antigens.

Animals↗
PubMed1982

Horse anti-type XIV Pneumococcus sera behave as cold agglutinins recognizing developmentally regulated antigens apart from the Ii antigens on human erythrocytes.

Haemagglutination studies with horse anti-type XIV pneumococcus sera have shown that they resemble cold agglutinin sera with anti-I specificity reacting more strongly with adult human erythrocytes than cord erythrocytes. However, their substantial reaction with iadult erythrocytes suggests that they react with other developmentally regulated antigens in addition to the I and i antigens.

Adult↗
PubMed1982

The antigens Ii, SSEA-1 and ABH are in interrelated system of carbohydrate differentiation antigens expressed on glycosphingolipids and glycoproteins.

Immunochemical studies using a group of monoclonal human auto-antibodies (anti-I and anti-i cold agglutinins) and a mouse hybridoma antibody (anti-SSEA-1) have revealed an interrelated system of carbohydrate antigens which also involves the major blood group antigens. The I and i antigens are expressed on branched and linear oligosaccharides respectively built of repeating N-acetyllactosamine units. These structures may serve as backbones to which specific monosaccharides are added to form the differentiation antigen termed SSEA-1 and the blood group H, A and B antigens. The expression of these carbohydrate antigens changes dramatically during (a) early embryogenesis in the mouse, (b) erythrocyte maturation and (c) gastric carcinogenesis in man. It is envisaged that these changing antigenicities reflect the stepwise addition or deletion of monosaccharides as a result of altered balance of glycosyl transferases. We now face the challenge of investigating the functions of these changing carbohydrate structures.

Animals↗
PubMed1982

Gastrointestinal mucins. Structures and antigenicities of their carbohydrate chains in health and disease.

The carbohydrate chains of gastrointestinal mucins are of wide interest because the same structures occur on glycoproteins and glycolipids of cell membranes and they express a variety of antigens recognized by polyclonal and monoclonal antibodies. In this article we summarize the information available on the structures found in three domains ('peripheral', 'backbone' and 'core' regions) of the carbohydrate chains of mucins. We discuss the various antigens expressed on these domains and the changes in their expression in benign and malignant diseases of the gastrointestinal tract. These antigens include the major blood group antigens A, B, H, Lea and Leb, the Ii antigens and some hybridoma-defined antigens termed SSEA-1, VEP8/9 and FC 10.2, all of which are now regarded as differentiation antigens with changing expression during embryogenesis and stages of cell differentiation. The functions of these diverse carbohydrate chains have eluded us thus far; they deserve systematic investigation as possible receptors involved in cellular interactions and reactions with microbial agents.

Antigens, Neoplasm↗
PubMed1981

Immunocytochemical studies of blood group A, H, I, and i antigens in gastric mucosae of infants with normal gastric histology and of patients with gastric carcinoma and chronic benign peptic ulceration.

Indirect immunofluorescence studies of blood group A, H, I, and i antigens were performed on the gastric mucosae and tumor tissues of patients with gastric carcinoma, on the mucosae of patients with chronic benign gastric ulceration, and on the mucosae of infants who had died of causes other than gastrointestinal disease. The following findings were of particular interest: (1) Normal 'secretor' type mucosae were distinguishable from 'non-secretor' type mucosae by the uniform staining of the A or H antigens at the surface and in the pits. Normal 'non-secretor' type mucosae showed little staining of the H or A antigens but, instead, there was staining with anti-I(Ma) antibody. Staining with anti-I(Step) and anti-i(Den) did not show a clear correlation with the 'secretor'/'non-secretor' status of the normal mucosae. (2) Apparently normal areas of gastric mucosae of patients with gastric carcinoma or the normal part of gastric mucosae of patients with benign gastric ulcer frequently showed focal areas of loss or gain of the blood group antigens as is often seen in gastric carcinoma tissues. (3) In the mucosae of patients with intestinal metaplasia there was marked loss of A/H antigens in 'secretors' and I(Ma) antigen in 'non-secretors'. (4) Staining characteristics of tissues from gastric carcinoma were:(a) Focal loss of the expected A/H or I antigens was observed with much variation in staining from area to area, but only a minority showed complete loss of the expected staining. (b) A majority of the carcinomas from 'secretors' showed foci of substantial staining with anti-I(Ma) in contrast to normal 'secretor' mucosae. This is probably due to incomplete biosynthesis of A/H determinants. (c) Incompatible A-like staining by a rabbit anti-A serum was observed in one out of nine adenocarcinomas from blood group B or O persons. (d) A few cases showed substantial i antigen staining. The aberrant expression of blood group A, H, I, and i antigens in neoplastic as well as in some areas of morphologically normal mucosa of patients with benign and malignant diseases of the stomach is discussed in the context of current biochemical knowledge.

ABO Blood-Group System↗
PubMed1981

The blood group Ii system: a carbohydrate antigen system defined by naturally monoclonal or oligoclonal autoantibodies of man.

The monoclonal anti-I and -i autoantibodies of cold agglutinin disease have drawn attention to a class of carbohydrate antigens which are of considerable biological interest. These antibodies have also served to illustrate the remarkable differences that can exist in the fine specificities of monoclonal antibodies directed against relatively simple antigens borne on hexa- to octasaccharide structures.

Agglutinins↗
PubMed1980

Sheep gastric mucins as a source of blood-group-I and -i antigens.

Gastric-mucosal glycoproteins of sheep have been shown to express the blood-group-I and -i antigens. The highest blood-group-I activities were found in glycoproteins lacking in blood-group-A and -H activities. In antigenically very active glycoprotein preparations, approx. 25% of the macromolecules expressed various blood-group-I and -i antigens, and these could be enriched by affinity chromatography with an anti-(blood group I) immunoadsorbent column. Additional blood-group-I and -i activities could be revealed by one cycle of Smith degradation of blood-group-A-active sheep gastric glycoproteins. Thus sheep gastric mucins are an abundant source of oligosaccharides with blood-group-I- and -i-active sequences.

Animals↗
PubMed1980

Expression of blood group I and i active carbohydrate sequences on cultured human and animal cell lines assessed by radioimmunoassays with monoclonal cold agglutinins.

Human monoclonal anti-I and anti-i antibodies, reactive with known carbohydrate sequences, have been used as reagents to quantitate (by radioimmunoassay) and visualize (by immunofluorescence) the expression of the various blood group I and i antigenic determinants in a variety of cultured cell lines commonly used in laboratory investigations. It has been shown that the antigens they recognize are widely distributed on the surface of human and animal cell lines, expressed in varying amounts in different cell lines and on individual cells within a given cell line. In two cell lines, a transformation-associated increase in the expression of I antigen was observed. Because of their precise specificity for defined carbohydrate chain domains, these autoantibodies have become valuable reagents in biological chemistry.

Agglutinins↗
PubMed1980

Structural and biological aspects of blood group I and i antigens on glycolipids and glycoproteins.

I and i oligosaccharide sequences are carried on a multiplicity of glycoproteins and glycosphingolipids. They occur as accessible or as partially or totally masked antigens on the surface of diverse cell types and in certain secretions. Changes in their expression may occur during differentiation, development, cell cycle and oncogenesis. There is suggestive evidence that they may be coupled to receptor systems on lymphocyte membranes. Monoclonal anti-I and i antibodies hold promise as reagents in biological chemistry.

Animals↗
PubMed1980

I and i antigens of human peripheral blood lymphocytes cocap with receptors for concanavalin A.

Surface immunofluorescence experiments using a human anti-i and two anti-I antisera have been performed on human peripheral blood lymphocytes. These are known to contain cold-reactive monoclonal IgM antibodies against the carbohydrate sequence: (formula: see text). A high proportion of B- and T-type lymphocytes express these I and i determinants. In the presence of anti-human immunoglobulin, the cold-reactive membrane-associated complexes of I-anti-I and i-anti-i become stabilized, and redistribution (with patching and capping) can be elicited at 37 degrees C. Dual fluorescence experiments have shown striking concordant staining of I or i (fluorescein) caps and patches with concanavalin A (rhodamine) reactive sites on normal and leukemic cells, suggesting that a proportion of I and i active structures of lymphocyte membranes are structurally associated or physiologically coupled with glycoproteins carrying oligosaccharides with branched mannosyl cores.

Antigens, Surface↗