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C Kinnon

Publications and source records attributed to C Kinnon.

At least 91 records · Page 5Linked to original sources
PubMed1992

Superoxide production by normal and chronic granulomatous disease (CGD) patient-derived EBV-transformed B cell lines measured by chemiluminescence-based assays.

We have compared assays for products of the neutrophil respiratory burst in normal EBV-transformed B cell lines stimulated with agonists of protein kinase C. Those measuring O2- directly or its immediate product, H2O2, were successful. Of these, the most sensitive were the lucigenin- and luminol-based chemiluminescence assays for O2- and H2O2 respectively. Cell lines from CGD patients, with X-linked or autosomal recessive genetic defects in the neutrophil NADPH oxidase, did not respond in these assays, indicative of their inability to produce O2-. The defects in the lines studied encompass both proteins forming the cytochrome b-245 membrane component, and the 47 kDa cytosolic component of the NADPH oxidase. The possession of the disease associated phenotype by these cell lines provides evidence that in the normal situation both neutrophils and B cells produce O2- via the same system.

Acridines↗
PubMed1992

Identification of CpG islands around the DXS178 locus in the region of the X-linked agammaglobulinaemia gene locus in Xq22.

The X-linked agammaglobulinaemia (XLA) gene locus has previously been mapped to Xq22. Genetic linkage analysis has shown tight linkage between the disease and the DXS178 locus and that DXS3 and DXS94 are the closet proximal and distal flanking markers, respectively, separated by a genetic distance of 10-12 cM. We attempted to construct a physical map of Xq22 using pulsed field gel electrophoresis (PFGE) and rare-cutting restriction enzymes in order to obtain a finite physical value for the distance between DXS3 and DXS94. However, these attempts were hampered by the large number of rare-cutting restriction enzyme sites around the DXS178 locus, indicative of the presence of CpG rich regions of DNA. We were able to construct a physical map of the sites close to DXS178 that suggests the presence of at least three, and perhaps as many as five, CpG islands. These are arranged on either side of DXS178, extending over about 550kb of genomic DNA. Each of these regions must be considered as being associated with a potential "candidate" gene sequence for the XLA gene and we have initiated a chromosome walk from DXS178 to the nearest of these islands.

Agammaglobulinemia↗
PubMed1992

The molecular basis of X-linked immunodeficiency disease.

The molecular bases of the X-linked immunodeficiency diseases remain largely undetermined. Two of the genes involved in these diseases have been isolated, namely the genes for X-linked chronic granulomatous disease and properdin deficiency, and substantial progress has now been made in identifying the genes which are defective in the other five diseases, Wiskott-Aldrich syndrome, X-linked severe combined immunodeficiency, X-linked agammaglobulinaemia, X-linked hyper-IgM and X-linked lymphoproliferative syndrome. We review here the nature of the diseases, progress made in identifying and isolating the genes involved and the prospects for improved prenatal detection, carrier status determination and treatment of these life-threatening conditions.

Granulomatous Disease, Chronic↗
PubMed1991

The murine heat-stable antigen: a differentiation antigen expressed in both the hematolymphoid and neural cell lineages.

The murine heat-stable antigen (HSA) and the p31 antigen are cell surface glycoconjugates which are transiently expressed during the development and differentiation of the hematolymphoid and neural cell lineages, respectively. We show here that monoclonal antibodies which react with these two species recognize a common antigenic determinant which is expressed on both HSA and p31, and the HSA and p31 share a common protein core. Differences in the molecular weights of the antigens most likely reflect variations in the extent of post-translational modifications. From these studies we conclude that these antigens are members of the same family of heat-stable antigens. Our results lead us to speculate on how these molecules are related, their function, and what role they play in cellular differentiation in hematolymphoid and neural cell development.

Animals↗
PubMed1990

RFLP and deletion analysis for X-linked chronic granulomatous disease using the cDNA probe: potential for improved prenatal diagnosis and carrier determination.

The molecular basis of X-linked chronic granulomatous disease (X-CGD) has recently been elucidated and the defective gene identified and isolated. Two restriction fragment-length polymorphisms have been identified using the X-CGD cDNA probe. We have analyzed eight families with X-CGD and seven normal, unrelated females and have demonstrated that these polymorphisms are not in linkage disequilibrium. This should increase to approximately 50% the proportion of families to whom first-trimester prenatal diagnosis can be offered. Unambiguous determination of carrier status in related females in informative families will also be possible. In addition, we have identified an apparently unique small deletion in the X-CGD gene in a family affected by this disease, members of which are not informative for either polymorphism. This will allow prenatal diagnosis and carrier determination in this family.

Chromosome Deletion↗
PubMed1990

Characterization of the murine heat-stable antigen: an hematolymphoid differentiation antigen defined by the J11d, M1/69 and B2A2 antibodies.

The heat-stable antigen (HSA) is a marker of hematopoietic differentiation in both the B and T cell lineages. The antigen is recognized by a series of monoclonal antibodies which includes J11d, M1/69 and B2A2, and in addition YBM5.10.4. We show here that all these antibodies recognize the same antigenic determinant which is expressed on a variably glycosylated membrane protein. Tunicamycin experiments show that the antigen is not carbohydrate in nature as it is expressed on two unglycosylated protein core molecules of molecular mass ca. 20 kDa and 17 kDa. Furthermore, the antigenic determinant appears to be lost following phosphatidylinositol-specific phospholipase C cleavage. Although the molecular mass of HSA appears to be heterogenous on cells of different lineages, these variations in size appear to be due primarily to differences in the extent of N-linked glycosylation, since both protein core molecules were found in all cell types investigated which express the antigen. These findings have important implications for the structure and function of this antigen and its role in hematopoietic development.

Animals↗
PubMed1989

Immunoglobulin and T cell receptor gene rearrangement and expression in B cell acute lymphoblastic leukemia.

Immunoglobulin and T cell receptor gene rearrangement and expression were investigated within B cell acute lymphoblastic leukemias (ALLs) that are thought to be representative of the early stages of normal human B cell development. Although the immunoglobulin heavy chain locus is rearranged in leukemic cells from all of these patients, only cells from pre-B ALL patients express mu chain protein. We have shown, however, that immunoglobulin heavy chain transcripts are expressed at levels similar to those found in normal B cells in all of these leukemic cell types and, in addition, some of the leukemias with a more mature phenotype also express immunoglobulin light chain mRNA. In contrast, leukemic cells which had rearranged T cell receptor gamma chain genes were not found to express gamma chain transcripts, indicating that the transcription of immunoglobulin and T cell receptor genes in these cells may be regulated in a lineage-specific manner.

Burkitt Lymphoma↗
PubMed1987

Differential regulation of T cell receptor gamma genes in immature thymocyte populations.

Immature thymocytes that lack both Lyt-2 (CD8) and L3T4 (CD4) expression can respond rapidly to stimulation with phorbol ester and calcium ionophore by expressing some gene products characteristic of mature, activated T cells. Here we studied the effect of such short-term stimulation on the number of copies per cell of RNA for components of the T cell receptor complex. Although, upon stimulation, mRNAs for T cell receptor beta chain accumulated to higher levels, the cells did not rapidly increase their expression of alpha-chain transcripts from rearranged or germ-line genes. Transcripts from the C gamma 1 (C gamma 13.4) and C gamma 2 (C gamma 10.5) genes were differentially regulated. The rarer C gamma 1 transcripts were strongly induced, while the initially abundant C gamma 2 transcripts showed a modest decrease in transcripts per cell within 24 h. Thus, the ratio of these two transcripts could be shifted dramatically prior to any significant change in the cellular composition of the population. These results suggest regulatory processes that may contribute to the observed expression of gamma products in vitro or in normal development.

Animals↗
PubMed1986

Activation of T cell antigen receptor alpha- and beta-chain genes in the thymus: implications for the lineages of developing cortical thymocytes.

Mammalian T lymphocytes mature in the thymus through a series of differentiation events that involve both rapid proliferation and extensive cell death. The mechanisms that govern these processes are currently unknown; however, both mitogenesis and death affect particular subpopulations of cells, suggesting the selective amplification and destruction of specific T cell clones. In mature peripheral T cells, proliferation is most commonly triggered by the recognition of antigen through the T cell antigen receptor complex. If antigen recognition also controls proliferation in the thymus, the differential expression of antigen receptor genes during maturation could play some role in determining the fate of developing T cells. In this study, we examined the expression of the alpha- and beta-chain genes of the T cell antigen receptor in different subpopulations of adult thymocytes. We compared two postmitotic populations--one that appears committed to die and one that appears mature--and several blast cell populations that are enriched for precursors of one or another presumptive lineage. We have found that Lyt-2-, L3T4- precursor thymocytes express much lower levels of both alpha- and beta-chain mRNA than the cells likely to be their immediate descendents. Furthermore, our results show that the cells of the major cortical lineage, which have at least a 95% probability of death, nevertheless express high levels of mature mRNA encoding both the alpha- and the beta-chains of the T cell antigen receptor. These results have important implications for the mechanisms involved in the overproduction and elimination of this major class of T lymphocyte.

Animals↗
PubMed1986

The synthesis and expression of HLA-A and -B antigens in Xenopus laevis oocytes.

Purified mRNA's encoding the HLA-A and -B antigen heavy chains or beta 2-microglobulin were prepared from human B lymphoid cells by positive hybridization selection procedures. The role of chain association in the biosynthesis and intracellular transport of HLA-A and -B antigens was investigated by injecting these mRNA species into Xenopus laevis oocytes and following the fates of the translated products by immunoprecipitation. When mRNA encoding beta 2-microglobulin from the B lymphoblastoid cell line MST was coinjected with mRNA encoding the HLA-A and -B antigen heavy chains from the Burkitt lymphoma cell line Daudi, fully assembled class I antigens were detected using the monoclonal antibody W6/32. This result suggested that there may be no defect in the mRNA encoding Daudi HLA-A and -B antigen heavy chains. When the state of maturity of the N-linked glycan units on these class I antigen heavy chains was assessed, they were found to have undergone some processing. In contrast, when mRNA encoding immunoglobulin M (IgM) was injected into oocytes, the glycan units of the IgM heavy chains were found to be in the unprocessed (high mannose) form. This result shows that Xenopus oocytes can process some eukaryotic glycoproteins of exogenous origin.

Acetylglucosaminidase↗
PubMed1983

Clathrin-coated vesicles purified from a human B lymphocyte cell line contain newly synthesized glycoproteins.

Clathrin-coated vesicles were purified from the cultured human B lymphocyte cell line RPMI 1788. These preparations were shown to be substantially free of contaminating membranes by the following criteria: (a) polypeptide composition, as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, (b) electron microscopy, (c) lack of binding of intact vesicles to concanavalin A-Sepharose, (d) migration of coated vesicles as a single major peak when applied to a Sephacryl S-1000 gel filtration column. An association between HLA-A, -B, and -DR antigens and immunoglobulins with coated vesicle fractions was demonstrated by lentil lectin affinity chromatography and by immunoprecipitation using antisera directed against these glycoproteins. [35S]Methionine pulse-chase experiments revealed that there was a kinetic correlation between the expression of newly synthesized glycoproteins and their presence in coated vesicles. These results indicate that coated vesicles may be involved in the transport of cell surface and secreted eukaryotic glycoproteins through the cell to their final destinations at the plasma membrane or in the extra-cellular medium.

B-Lymphocytes↗
PubMed1981

Properties of N-acetyl-beta-D-hexosaminidase from isolated normal and I-cell lysosomes.

Using a combination of differential centrifugation and free flow electrophoresis (Harms, E., Kern, H., and Schneider, J. A. (1980) Proc. Natl. Acad. Sci. U. S. A. 77, 6139-6143) a single population of highly purified lysosomes was obtained from normal, I-cell disease type 1, and I-cell disease type 2 cultured fibroblasts. Our findings indicate that most of the residual acid hydrolase activities remaining within the I-cell fibroblasts are localized in the lysosomes, analogous to normal cells. Characterization of the carbohydrate-dependent properties of the lysosomal N-acetyl-beta-D-hexosaminidase revealed that the I-cell and normal enzymes do not contain a significant proportion of neuraminidase-susceptible sialic acid residues, interact poorly with the beta-galactose-specific lectin Ricinus communis and are highly sensitive to endohexosaminidase H treatment, indicating that the oligosaccharide units of both the I-cell and normal lysosomal N-acetyl-beta-D-hexosaminidase are predominantly of the high mannose type. The I-cell and normal lysosomal N-acetyl-beta-D-hexosaminidase, however, differed in their endocytotic properties. In contrast to the high rate of endocytosis of the normal lysosomal enzyme (7.8%/mg/h), the I-cell type 1 lysosomal enzyme failed to be endocytosed into Sandhoff cells indicating an absent or altered phosphohexyl recognition marker on the I-cell enzyme. Examination of the normal extracellular N-acetyl-beta-D-hexosaminidase revealed the presence of predominantly high mannose-type oligosaccharide units, similar to the corresponding lysosomal enzyme, although properties typical of complex-type oligosaccharide chains were also evident. In contrast, the secreted I-cell enzyme revealed the presence of oligosaccharide units predominantly of the complex type indicating that the I-cell N-acetyl-beta-D-hexosaminidase has had high mannose-type oligosaccharide chains modified to complex-type probably in the Golgi or GERL region prior to secretion from the cell.

Acetylglucosaminidase↗