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Biomedical subjects

L Rivat

Publications and source records attributed to L Rivat.

At least 37 records · Page 2Linked to original sources
PubMed1976

Deletion of hinge region of human myeloma IgG1 molecule (protein LEC) associated with nonexpression of G1m (3) and Km (1, 2) allotypes. A possible genetic explanation at the DNA level.

In this paper we report the structural basis for the nonexpression of G1m(3) and Km (1,2) allotypes in an IgG1 (kappa) human myeloma protein (protein LEC). Heavy and light chains spontaneously dissociate in sodium dodecyl sulfate polyacrylamide gels. Light chains appear to be covalently S-S bonded. Analysis of cysteine-containing peptides shows that the heavy chain of the IgG protein LEC has a deletion of residues 216-230, thus encompassing the entire hinge region. An arginine residue, characteristic of the G1m(3) marker is present at position 214. An alanine at position 153 and a leucine at position 191 of the light chain, characteristic of the Km (1, 2) allotypes, are present. It is likely that the double Km and Gm lack of expression is the result of the deletion. The genetic implications of the sequence of this protein are discussed.

Amino Acid Sequence↗
PubMed1976

Antigenic determinants of heavy chain variable regions: immumological typing of the human immunoglobulin VHIII subgroup.

An antigenic determinant of the VHIII variable region subgroup was defined by means of a heterologous specific antiserum using a hemagglutination inhibition procedure. The specificity of this antiserum was established in inhibition experiments with proteins either of known primary structure or belonging to a definite VH subgroup. A series of IgG, IgA, IgM and IgD monoclonal proteins was examined for the presence of this VHIII subgroup antigenic determinant. The data showed that 50% of the IgG, 62% of the IgA, 55% of the IgM and 41% of the IgD were VHIII-positive, and that certain "blocked" monoclonal immunoglobulins belonged to this subgroup. A preferential association of the VHIII antigenic determinant with the IgG1 and IgG3 subclasses was observed among IgG myeloma proteins while the preferential association was only observed with the IgG1 subclass when anti-Rh antibodies were studied. The VHIII subgroup exhibited nonallelic behavior.

Epitopes↗
PubMed1976

Quantitative studies of Gm allotypes. I. Reappraisal of the method using an autoanalyzer.

In this study, various parameters for the autoanalyzer hemagglutination-inhibition circuit applied to Gm studies, were examined. Details are given of modifications of this circiut and related methodology, that improve its precision and the reproducibility of results: use of a cells counter, effects of temperature, PVP, Tween 20, anti-Gm concentration, etc. The effects of age, storage and freezing on quantitative Gm allotypes antigenicity are also stressed.

Antibodies, Anti-Idiotypic↗
PubMed1976

Expression of genetic markers of erythrocyte immunoglobulin G autoantibodies in autoimmune hemolytic anemia.

The Gm allotype constitution of the autoantibody molecules and the serum Gm phenotypes were determined in 19 patients with autiommune hemolytic anemia of IgG type. The results showed that the known heterogeneity of the antierythrocyte autoantibodies in this disease concerns not only the immunoglobulin class and the isotypic subclass, but also the genetic markers of these molecules. Evidence was obtained that the anomalous production of antierythrocyte autoantibodies is polyclonal, that thse autoantibodies belong mainly to the IgG1 isotypic subclass, and that they have a preference for the Gm(1) allotype. In addition, certain of the findings point to a preferential expression of the Gm(1,21) haplotype.

Anemia, Hemolytic, Autoimmune↗
PubMed1976

Evidence for "deleted" or "silent" genes homozygous at the locus coding for the constant region of the gamma3 chain.

Three uncommon stable Gm haplotypes, Gm3;23;--, Gm1,2,17;..;-- and Gm1,17;..;-- have been transmitted through 3 generations of two related Lebanese and Syrian families. No pathological consequence was noted in seven individuals, aged 14--65, whose sera were deficient for all the allotypes carried by the IgG3 chains. Among the different genetic events which could have produced these haplotypes (alteration of a regulatory gene, point mutation, gene hybridization, gene deletion), it appears that a structural deletion is the most probable explanation. The observed data can be explained by either a partial or a total deletion of the constant portion of the IgG3 heavy chain.

Adolescent↗
PubMed1975

Gm and Inv allotypes in premature infants.

Using haemagglutination inhibition tests specific for Gm allotypes and similar tests for IgG4, the placental transfer of the four IgG subclasses from mother to foetus has been confirmed. The Gm phenotype of a cord serum is often identical to that in the corresponding maternal serum. However in 31 cases out of the 90 tested, Gm allotypes were present in the cord serum that were not present in the maternal serum. These allotypes produced by the foetus in utero are dependent on a paternal gene. The logarithm of the IgG level increase proportionately with gestational age (r = 0.59 p less than 0.001).

Female↗
PubMed1975

Gm and Inv allotypes in French Guiana Indians.

Data from 302 individuals belonging to three populations of French Guiana Indians are reported. All the phenotypes except two can be explained by three haplotypes: Gm1,21, Gm1,2,21 and Gm1,10,11,25. The gene frequencies found in the present study are generally in accordance with those previously described among other South American Indians. For the Inv1,2 gene a high value has been found for the Wayanas and the Oyampis, but a difference appears for the Emerillons who possess a low frequency.

Blood Group Antigens↗
PubMed1975

Gm and Inv allotypes in a Gypsy sample.

Serum samples from 226 Gypsies were tested for Gm(1,2,4,5,8,10,11,14,17,21,23,25) and for Inv(1,2). The Gm phenotypes found are very numerous and the more frequent among this population are: Gm(4,5, 8,10,11,14,17,23,25) and Gm(1,2,4,5,8,10,11,14,17,21,23,25). All the phenotypes except three can be explained by nine haplotypes: Gm4,5,8,10,11,14,23,25, Gm1,4,5,8,10,11,14,23,25, Gm4,5,8,10,11,14,25, Gm1,17,21, Gm1,10,11,17,25, Gm1,2,17,21, Gm1,8,17,21, Gm1,8,17,21,23 and Gm1,5,10,11,14,17. The haplotypes Gm1,17,21, Gm1,2,17,21, Gm4,5,8,10,11,14,25 (with or without Gm[ 3]) are all three common among Caucasoids, Gm1,4,5,10,11,14,23,25 (common among Mongoloids) and Gm1,5,10,11,14,17 (common to Negroids). For the Inv system, this population possesses a very low frequency of Inv(1) and Inv(2).

Ethnicity↗
PubMed1975

An abnormal Cgamma 4 gene among the negro population.

An analysis of the IgG4-CH3 antigenic determinants by means of specific antisera using a hemagglutination-inhibition procedure among different populations has been done. Thus 3.67% of sera from Negroids have been found completely deficient in normal IgG4 subclass. Sera without normal IgG4 contained the other IgG subclasses. Family studies shown the transmission of an abnormal Cgamma 4 gene. Hypothesis of gene deletion, point mutation or gene hybridization were postulated. This last hypothesis seems the most valuable.

Africa↗