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S E Cullen

Publications and source records attributed to S E Cullen.

53 records · Page 3Linked to original sources
PubMed1977

Ag-B-linked analogue of Ia antigens in the rat.

The reactions of Lewis rat lymphocyte membrane antigens with two alloantisera, BN anti-Lewis and BN anti-Fischer have been studied. Three lines of evidence indicated that these antisera reacted with cell surface antigens homologous to Ia antigens of the mouse. 1) After absorption with Lewis platelets, the antisera killed only 40 to 50% of Lewis spleen cells. The majority of such cells were shown to be Ig-positive B cells by the examination of reaction patterns on lymphocytes after separation on nylon wool into T cell- and B cell-enriched subpopulations. 2) SDS-PAGE analysis of solubilized Lewis spleen cell antigens precipitated with these antisera revealed that the platelet-absorbed antisera reacted with molecules comparable in size to mouse Ia antigens (mw approximately equals 35,000 and 28,000). The unabsorbed sera reacted with these molecules and with additional molecules corresponding in size to mouse K and D antigens (m.w. = 45,000). 3) Neither of these antisera killed significant numbers of spleen cells from the partially congenic strain F.BN (seventh backcross homozygotes), a Fischer rat to which the Ag-B.3 allele is being transferred by repetitive backcrossing, indicating that the genes coding for these Ia-like antigens in the rat are linked to the Ag-B locus.

Animals↗
PubMed1977

A human alloantiserum precipitates Ia-like molecules from chronic lymphocytic leukemia cells.

Alloantigens specific for human B lymphocytes can be identified with selected antisera. These antigens have similarities to murine Ia antigens in that they are found on human B lymphocytes and are controlled by genes linked to genes controlling HLA. Chronic lymphocytic leukemia cells bearing B cell antigens were labeled with 3H leucine and the membrane components reacting with the B cell antisera isolated by immunoprecipitation. These membrane components had m.w. of 33,000 and 24,000 daltons similar to the murine Ia antigens. The results complete the homology of murine Ia and human B cell alloantigens.

Animals↗
PubMed1977

Genetic control of the humoral response to an H-2 public specificity.

The humoral response of mice to an H-2 public specificity, termed H-2. '28' was found to be under genetic control. The genes determining this specificity were mapped to both the H-2K and H-2D regions, suggesting possible structural homologies between the products determined by these two regions. Genetic analyses indicated that a single non-H-2-linked gene regulates the anti-H-2. '28' response. In a backcross study, no linkage was detected between this putative H-2. '28' Ir gene and either the V H region or the Ly-2 locus to which the K-light chain locus is linked. Thus, a regulatory rather than a structural genetic locus seems a more likely basis for differences in response to this antigen. Our data further indicate that control of the humoral response to H-2. '28' is determinant specific since responses of the same backcross mice to other K and D alloantigens were not found to be subject to the same control.

Animals↗
PubMed1976

Evidence for more than one Ia antigenic specificity on molecules determined by the I-A subregion of the mouse major histocompatibility complex.

Ia antigenic specificities determined by the I-A subregion of the mouse major histocompatibility complex have been examined in strain B10.D2 (H-2d), C57BL/10 (H-2b), and in a (C57BL/6xDBA/2) hybrid (BDF1; H-2b/d). Detergent solubilized, 3H-leucine-labeled antigen preparations were mixed with appropriate alloantisera and precipitation was induced either by addition of goat anti-mouse gamma-globulin or by addition of protein A-bearing Staphylococci. Sequential precipitation analysis showed that in strain B10.D2, Ia specificities 8 and 11 were co-precipitable, and that in strain C57BL/10, Ia specificities 8 and 9 were co-precipitable. In contrast, precipitation of specificities 9 and 11 from a BDF1 antigen preparation showed that these two Ia specificities were on separate molecules. The genetic implications of these data are discussed.

Animals↗
PubMed1976

An improved method for isolation of H-2 and Ia alloantigens with immunoprecipitation induced by protein A-bearing staphylococci.

Mouse alloantigens, including the histocompatibility (H-2) and immune response linked (Ia) antigen molecules, can be readily isolated by a new precipitation technique utilizing protein A-bearing, fixed Staphylococci. The antigens are prepared by radiolabeling mouse spleen cells with 3H-leucine, solubilizing with the non-ionic detergent Non-Idet P-40, and purifying by affinity chromatography with lentil lectin coupled to Sapharose. The antigen preparations are mixed with appropriate alloantisera, and immune complexes formed in the mixture are then bound by the protein A sites on the Staphylococci. The organisms, Staphylococcus aureus, Cowan I strain (ATCC 12598), are heat inactivated and fixed, and are a stable, uniform IgG-binding reagent, especially when stored frozen. The antigen-antibody complexes are easily eluted from the organisms for electrophoretic analysis. The precipitation mediated by the organisms is more efficient, rapid, and artifact-free than the traditional "sandwich" precipitation technique involving anti-globulin reagents.

Animals↗
PubMed1975

Serologic and biochemical studies of the Ia system of the mouse H-2 gene complex. Further evidence for I-C subregion.

Three antisera were made against B10.A(5R) tissues to show the presence of an I-Cd subregion in that strain: 1) B10 anti-B10.A(5R) [anti-Dd, I-Cd]; 2) (B10 times C3H.9L) F1 anti-B10.A(5R) [anti-Ddi1; 3) (B10 times HTI)F1 anti-B10.A(5R) [anti-I-Cd]. Serologic analyses of the antisera clearly showed the presence of an Id segment in B10.A(5R) and provided further evidence for the existence of a new I-C subregion. These anti-I-Cd sera define the Ia.7 specificity and analyses of several recombinants map Ia.7 within the I-C subregion. Ia.7 is present in I-Ck, I-Cd and Ip strains. Biochemical analyses showed that the Ia.7 molecule has a molecular weight of 31,000 and is distinct from the 46,000 m.w. H2K or D molecules. The possible roles of the I-C region in immune response, mixed lymphocyte reaction, and graft-vs-host reaction are discussed.

Absorption↗
PubMed1975

Ir-associated murine alloantigens. Serological and chemical definition of Ia specificities associated with the H-2-b haplotype.

Strains bearing recombinant H-2 haplotypes with known positions of recombination have been used to demonstrate antibodies reacting with Ia antigens associated with the H-2-b haplotype in several H-2 antisera. Two new Ia specificities, Ia.8 and Ia.9, both determined by genes in the Ir-1A subregion, have thus been defined, and the strain distribution of these specificities has been determined. Immunoprecipitation of radio-labeled membrane antigens has been used to characterize Ia.9 and to distinguish it chemically from Ia.7 in a membrane preparation from a strain possessing both specificities.

Animals↗
PubMed1974

Membrane molecules determined by the H-2 associated immune response region: isolation and some properties.

Membrane associated molecules that are probably glycoproteins could be specifically precipitated from NP-40 detergent solubilized extracts of radiolabeled mouse spleen or lymph node cells by antisera produced in congenic strain combinations differing only in the Ir gene region which is linked to the H-2 genes. These Ir region products were designated Lna (lymph node antigen) to conform to previous serological work.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of unreduced specific immune precipitates revealed the presence of a possible dimer form, while reduced samples showed only a single peak equivalent to 30,000 daltons. Thus the Lna molecules are clearly distinct from the H-2D and H-2K molecules, which are about 45,000 daltons. Anti-Lna antibodies of different specificity can be present in a single serum; there were at least two separate antigen molecules present in one haplotype tested.

Animals↗
PubMed1972

The molecular basis of codominant expression of the histocompatibility-2 genetic region.

H-2 alloantigens in an intact, undegraded form can be solubilized by the nonionic detergent NP-40 and isolated by indirect immunoprecipitation and electrophoresis in sodium dodecyl sulfate on polyacrylamide gels. With the use of an immunological precipitation method, the question about the number of cellular H-2 gene products in heterozygous cells has been partially resolved. At least four separable gene products were detected in cells heterozygous at the H-2 genetic region-one for each of the H-2D genes of the two parental haplotypes, and one for each of the H-2K genes of the two parental haplotypes. This is in contrast to the two H-2 gene products reported previously for cells homozygous at the H-2 region. The findings establish that the two parental H-2 haplotypes on homologous chromosomes in heterozygous cells are ultimately expressed as different glycoprotein molecules.

Acrylamides↗