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M Vaiman

Publications and source records attributed to M Vaiman.

At least 73 records · Page 4Linked to original sources

Molecular genetic analyses of the major histocompatibility complex in pig families and recombinants.

Five HLA probes, one corresponding to class I genes, two corresponding to distinct class II light chain genes, DR beta and DQ beta, and two to class II heavy chain genes, DR alpha and DQ alpha, were used to analyse the genomic DNA of the pig. Three informative SLA typed families and four SLA recombinants were studied by Southern blot analysis. About 16 restriction fragments, generated by EcoR1 or Hind III endonucleases, were revealed for each individual, either with the class I probe or the DR beta probe. The number of restriction fragments which hybridized with the other probes was generally lower. Several restriction fragment-length polymorphisms were found and these segregated with SLA haplotypes. The studies on SLA recombinants showed that SLA DR beta- and DQ alpha-like genes are probably tightly clustered within the SLA-D-MLR region.

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Assignment of MHC in swine to chromosome 7 by in situ hybridization and serological typing.

Mapping of the MHC in swine (SLA) was achieved by direct in situ hybridization to chromosome preparations. We took advantage of the fact that the cDNA probe coding for class I HLA-B7 antigen cross-hybridizes with swine genomic DNA. By nick-translation, 35S nucleotides were incorporated to a specific activity of 2,7 10(7) cpm/ug. Analysis of 91 randomly selected labeled metaphases revealed highly significant labeling on chromosome 7. The SLA complex is most probably located at the proximal half of the long arm, as indicated in families carrying a modified chromosome 7 and heterozygous for SLA. The abnormal chromosome was always inherited with a specific haplotype whereas the other parental haplotypes were found in association with the normal 7.

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Expression of beta 2-microglobulin on preimplantation pig embryos.

The expression of beta-2 microglobulin (beta 2m), a protein associated with the histocompatibility antigens of the pig complex (SLA), was studied in preimplantation embryos between the segmentation stage and the beginning of elongation (day 12). The antigen was visualized at the ultrastructural level by immunocytochemical techniques using peroxidase or colloidal gold particles as labels. beta 2m expression appeared to parallel trophoblast differentiation. No positive reaction was obtained before the early blastocyst stage. From this stage on, labelling was observed on the apical surface of the trophectoderm cells.

Animals↗

Monoclonal antibodies to HLA recognize monomorphic and polymorphic epitopes on BoLA.

Fourteen monoclonal antibodies recognizing monomorphic and polymorphic epitopes on class I and class II antigens of the human MHC have been assayed on lymphocytes of a panel of 20-150 BoLA typed bovine animals from 12 different breeds. Some monomorphic antibodies cross-reacted and others did not. Two polymorphic monoclonal antibodies in man recognize a polymorphism in cows that follows allospecificities (BoLA-w3, w9) already described. Immunoprecipitation experiments with monomorphic anti-B2m and anti-HLA-DR monoclonal antibodies have shown that these cross-reactions concern BoLA antigens. They also revealed that Ia-like antigens in cattle present the same two chain features characterized in other species.

Animals↗

Monoclonal antibodies as a tool for phylogenetic studies of major histocompatibility antigens and beta 2-microglobulin.

The cross-reactivity of several monoclonal antibodies recognizing monomorphic determinants of human HLA-A, B, C, and DR antigens and human beta 2-microglobulin (beta 2m) has been studied on peripheral blood leukocytes in 24 different species. An monoclonal HLA-A-, B-, and C-specific antibody and four monoclonal HLA-DR-specific antibodies cross-reacted with cells from all the primate species tested. Furthermore, antibodies HLA-DR-specific were positive with peripheral blood leukocytes (PBL) from cows, goats, sheep, horses, and dogs. Two monoclonal beta 2m-specific antibodies, which were positive with PBL from certain primates, also reacted with cells from cows, goats, sheep, horses, and dogs. Two other beta 2-m-specific antibodies reacted only with PBL from chimpanzees. No reaction could be detected with all our reagents in other classes tested (birds, reptiles, amphibians, and Teleostei).

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The pig histocompatibility system SLA: serological study on a group of antigenic specificities.

The report presents an analysis of a group of class I SLA reagents which were highly correlated within one cluster in a previous analysis. Further population and family studies, and selected purification of several of these reagents led to the identification of 4 distinct specificities, namely SLA A 15, B 18, C 1 and A 16. Three of them, SLA A 15, B 18 and C 1, are actually in strong linkage disequilibrium and represent the main SLA haplotype in the Large White breed. SLA A 16 is present essentially in the Landrace breeds. SLA A 16 displays a strong cross-reaction with SLA A 15 and there is another specificity in linkage disequilibrium with SLA A 16 which cross-reacts with SLA B 18. Altogether, the strong linkage disequilibrium and the high degree of cross-reactivity among the allelic products of the SLA complex explain the failure to detect the diversity of our reagents in previous studies.

Absorption↗

[Incompatible SLA bone marrow graft in swine after fractional irradiation and administration of cyclosporin A].

A series of fractionated partial irradiations which consisted of either 3 gray x 6 times or 3 gray x 4 times, combined with pharmacological immunosuppression (Cyclosporin A: Cs-A) ensure a SLA semidifferent bone marrow graft in the pig. Bone marrow and peripheral blood lymphocytes chimerism was readily detectable. No graft versus host disease (GVHD) symptoms were noticed as long as Cs-A was given at a sufficient dose. However when Cs-A treatment was stopped GVHD or rejection of the graft developed rapidly.

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Characterization of class II histocompatibility antigens in pigs.

The D region of the SLA complex in the pig has been studied by immunochemical and sequential immunoprecipitation techniques as well as the redistribution of membranous antigens (capping). The molecules identifies by the anti-Ia sera were solubilized by NP 40, purified on lectin and precipitated. Polyacrylamide gel electrophoresis under dissociating conditions shows that these molecules are made up of two chains whose molecular weights are 32000 and 26000 daltons respectively. Sequential immunoprecipitation and capping experiments indicate that two distinct types of Ia molecules exist. At least a part of the nylon-wood-adherent lymphocyte population express both types of molecules.

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Analysis of alloantisera against bovine lymphocytes. Joint report of the 1st International Bovine Lymphocyte Antigen (BoLA) workshop.

The results and agreements of the 1 international BoLA workshop, held in Edinburgh, Scotland in August 1978, are reported. Most of these concern the results from a comparison test of 249 alloantisera to bovine lymphocytes, the antisera being contributed by 9 laboratories. These sera were compared directly in Edinburgh on a panel of lymphocytes from 130 cattle of 21 breeds. In the microlymphocytotoxicity test used 75% of the sera reacted. Sixty eight of these sera were grouped into clusters according to their reaction patterns against the lymphocyte panel. Eleven of these clusters were clearly defined and were given workshop BoLA designations. In addition 22 sera were assigned to subgroups of the agreed clusters. There was no evidence that the method of production of the sera had any effect on their specificity. Although genetic data was not available, the phenotypes of the test panel of lymphocytes are consistent with the clusters detecting antigens controlled by multiple alleles at a single autosomal locus. It was agreed to name the genetic region where this putative locus is located BoLA (bovine lymphocyte antigen).

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Characterization of pig lymphocyte subpopulations by adherence to nylon wool.

The property of adherence to nylon wool was used to separate and characterize pig blood lymphocyte subpopulations. Thymus-dependent null cells proved the least adherent lymphocytes, and B cells, bearing surface Ig or Fc receptor, the most adherent. sIg+ lymphocytes detected by immunofluorescence and by 51Cr release cytotoxicity showed similar frequency and adherence properties. Lymphocytes rosetting with SRBC in PBS or in dextran had similar adherence patterns and showed both non-adherent and adherent components. Lymphocytes bearing major histocompatibility complex (MHC) Ia-like antigens shown by eosin exclusion or 51Cr release cytotoxicity were enriched in the adherent fraction, but also occurred in significant numbers in the non-adherent fraction. Non-adherent Ia+ cells were predominantly sIg- and probably T cells, whereas the adherent Ia+ group included the sIg+ cells and some sIg- cells.

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Influence of the major histocompatibility complex in the pig (SLA) on serum haemolytic complement levels.

Sera from fourty-six non-congenic adult pigs from one inter-related herd were tested for their haemolytic serum complement levels. A comparison of these data with the major histocompatibility complex (SLA) genotypes of these animals resulted in the demonstration of highly significant differences in lytic activity between sera obtained from animals of two distinct SLA haplotypes. These data showed a high correlation between the SLA complex and the level of haemolytic activity.

Animals↗

Presence of SLA and Ia-like antigen on boar spermatozoa.

Several parameters for serological tests on boar spermatozoa were studied, and a reliable technique was developed and employed. Using SLA (the MHC system in pig) genotyped boars, and specific reagents, SLA and Ia-like antigens were demonstrated on the sperm using both the cytotoxic and the absorption test. No SLA activity was detected in the seminal fluid.

Animals↗

Presence of soluble SLA histocompatibility antigen in pig plasma.

The major histocompatibility antigens of the pigs (SLA 1 and SLA 15) were solubilized by papain and then iodinated according to Greenwood's chloramine T method. These antigen preparations were used in radioimmunoassays for the detection of soluble inhibitors in pig plasma. Specific soluble substances were demonstrated in addition to a certain amount of cross-reactivity with other so far unidentified antigens.

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