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Biomedical subjects

T Feizi

Publications and source records attributed to T Feizi.

At least 217 records · Page 12Linked to original sources
PubMed1975

The blood group I and i antigens of amniotic fluid. I. Association of I and i antigens with blood group A, B and H antigens.

Human amniotic fluid has been shown to contain blood group i as well as I antigens. Crude extracts of amniotic fluids at 16-23 weeks of gestation were in general more active than those obtained at term. A pool of amniotic fluids which had A, B, H as well as I and i activity was fractionated with an insolubilized anti-I (Group 3 type) immunoadsorbent column. There was evidence for the occurrence of I and i determinants on macromolecules carrying A, B and H determinants, for the fraction specifically retained by the column was enriched by 50-60-fold in I and i activity and by at least 10-fold in A, B and H activity. In the fraction not retained by the column there remained the bulk of the A, B, H activity in addition to I activity of Group I type which is known to be distinct from the Group 3 determinant. With the aid of specific immunochemical fractionation procedures, human amniotic fluid should prove useful in structural studies of the several I and i determinants and of their relationship to other blood group determinants.

ABO Blood-Group System↗
PubMed1975

A common idiotype on human macroglobulins with anti-I and anti-i specificity.

The reactions of an idiotypic antiserum prepared against an anti-I cold agglutinin (Da) were studied in radioimmunoassays which were designed to detect partial rather than complete idiotypic cross-reactions among cold agglutinins with anti-I and anti-i activity. Proteins showing strong idiotypic cross-reactions by gel precipitation could not inhibit the binding of 125I-labelled Da to anti-Da (individual specificity). It was necessary to use 125I-labelled cross-reactive proteins in order to demonstrate cross-idiotypic specificity and even the choice of the reference cross-reactive protein was important. The use of the 125I-labelled Fab fragment of a cross-reactive anti-I cold agglutinin (Low) allowed the detection of an idiotypic determinant common to at least 73% of cold agglutinins with specificity for the I-i antigen complex. Among these were two transiently occurring cold agglutinins following M. pneumoniae infection and infectious mononucleosis. This idiotypic determinant was not detected on cold agglutinins with anti-Pr specificity or on isolated monoclonal IgM or IgG lacking cold agglutinin activity, but it was present in low concentrations in pooled IgG. The common idiotypic determinant was found on IgM kappa cold agglutinins belonging to different VK subgroups and on an IgM lambda protein. A knowledge of the structural basis of such idiotypic cross-reactions among proteins from unrelated individuals should provide important information about the genes controlling the synthesis of site-related regions of antibodies.

Agglutinins↗
PubMed1974

Idiotypic specificity of surface immunoglobulin and the maturation of leukemic bone-marrow-derived lymphocytes.

Certain cases of chronic lymphocytic leukemia are associated with monoclonal immunoglobulins in the serum. In the present study it was possible to demonstrate that the surface immunoglobulin of the leukemic lymphocytes was idiotypically identical to the serum monoclonal immunoglobulin of the same individual. This was done through the use of fluorescent antibodies that were prepared against the isolated immunoglobulin M kappa serum protein from patient Ei. Such antibodies, after absorption, failed to react with the lymphocytes of other individuals. Capping experiments indicated that both the immunoglobulin M and the immunoglobulin D on the leukemic cells possessed the same idiotypic specificity.A population of plasma cells was also identified in the peripheral blood of patient Ei that showed strong intracellular staining with the idiotypic antiserum and was the apparent source of the specific serum immunoglobulin. The accumulated evidence indicates that the plasma cells were derived from the leukemic lymphocytes by a process of differentiation. Surface immunoglobulin D disappeared and surface immunoglobulin M decreased markedly in this process.

Aged↗
PubMed1972

Immunochemical studies on blood groups. LIV. Classification of anti-I and anti-i sera into groups based on reactivity patterns with various antigens related to the blood group A,B,H, Le a, Le b and precursor substances.

Quantitative precipitin assays were carried out with eleven anti-I and five anti-i cold agglutinin sera. Their reaction patterns with precursor substances and with certain antigens related to the A, B, H, Le(a), and Le(b) substances revealed at least six types of I and four types of i specificity. All of the I and i determinants appear to be represented in varying amounts on that fraction of the ovarian cyst precursor substance OG which was precipitated by 20% ethanol (OG 20% 2X). Only some of these determinants can be detected in the first periodate oxidation stages of A, B, and H substances, in cow substances, and in hydatid cyst fluid.

ABO Blood-Group System↗
PubMed1972

Light chain sequences of human IgM cold agglutinins (variable-region subgroups amino-acid sequence-kappa light chain-N-terminal).

The amino-terminal amino-acid sequence has been determined for the kappa light chains of nine IgM cold agglutinins with specificity for blood group-related carbohydrate antigens. Six of the nine sequences corresponded to the prototype VK(III) subgroup pattern, two to that of subgroup VK(II), and only one to the VK(I) subgroup. This distribution of kappa subgroups differs markedly from that of normal and myeloma proteins sequenced to date, where the VK(I) subgroup is more prevalent than either VK(II) or VK(III). Evidence is presented that supports the conclusion that the unusual subgroup distribution relates to the antibody property itself and not to some other attribute of these molecules.

Amino Acid Sequence↗
PubMed1971

Immunochemical studies on blood groups. XLVII. The I antigen complex--precursors in the A, B, H, Lea, and leb blood group system--hemagglutination-inhibition studies.

A partially purified blood group-like substance obtained from milk showed I activity with 2 of 21 anti-I sera. With these antisera, certain human ovarian cyst substances considered to be precursors of the A, B, H, Le(a), and Le(b) substances also showed I activity comparable to the milk material. Strong I activity could be produced by one-stage periodate oxidation and Smith degradation of human ovarian cyst A and B substances, or of hog mucin A + H substance, or by mild acid hydrolysis of human saliva or ovarian cyst blood group B substance. The two sera indicate that I specificity appears at intermediate stages in the biosynthesis of the A, B, H, Le(a), and Le(a) substances. Anti-I sera differ strikingly in their specificities, indicating substantial heterogeneity of the I determinants.

ABO Blood-Group System↗
PubMed1970

The emergence of antibodies with either identical or unrelated individual antigenic specificity during repeated immunizations with streptococcal vaccines.

Electrophoretically monodisperse antibody components in rabbit antisera to the carbohydrates of the Groups A and C streptococci have been examined for their individual antigenic specificity. In these antibody components which were isolated by preparative electrophoresis, individual antigenic specificity was confined to the specific antibody and was absent in the nonantibody gamma-globulin. Radioprecipitation experiments and the use of immune absorbent columns constructed from goat anti-antisera, which had been absorbed with fraction II, revealed that all the specific antibody in an electrophoretically monodisperse component was reactive with the homologous anti-antibody. Antibodies with either identical or distinct individual antigenic specificities may occur in the same rabbit with repeated immunizations. Antibodies with identical antigenic specificity had identical electrophoretic mobility, whereas antibodies with unrelated antigenic specificities had distinct electrophoretic mobilities. In the interval between immunizations, if antibody to the carbohydrate antigen was absent, there was no detectable antibody with individual antigenic specificity.

Animals↗