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W C Raschke

Publications and source records attributed to W C Raschke.

At least 37 records · Page 2Linked to original sources
PubMed1981

Evidence that the Abelson virus protein functions in vivo as a protein kinase that phosphorylates tyrosine.

Both lymphocytes and fibroblasts that have been transformed by ABelson murine leukemia virus contain 6- to 12-fold increased levels of the rare modified amino acid phosphotyrosine in their proteins. This observation, coupled with the fact that the p120 protein encoded by this virus has been shown to undergo an apparent autophosphorylation to yield phosphotyrosine in vitro, suggests that Abelson virus encodes a protein kinase that phosphorylates tyrosine in transformed cells. These results are similar to those obtained previously with Rous sarcoma virus and suggest, by analogy, that the modification of cellular polypeptides through the phosphorylation of tyrosine may be involved in cellular transformation by Abelson virus. p120 isolated from transformed cells contains phosphoserine, phosphothreonine, and phosphotyrosine. The phosphotyrosine is found at two sites in the protein. p120 therefore may be a protein kinase that undergoes autophosphorylation in vivo.

Abelson murine leukemia virus↗
PubMed1980

Transformation by Abelson murine leukemia virus: properties of the transformed cells.

Ab-MuLV transforms mouse 3T3 fibroblasts, macrophages, and lymphocytes, which have properties of immature cells in the B-lymphocyte differentiation pathway. Differences in expression of intracellular immunoglobulin and surface antigens the lymphoma lines suggest that more than one B-lymphocyte differentiation stage may be transformed, each of which must be before the B lymphocyte acquires cell-surface immunoglobulin receptors for antigen and antigen sensitivity. The plasmacytomas induced by Ab-MuLV plus pristane tested thus far show no evidence of infection by Ab-MuLV. The transformation of these immunoglobulin-secreting cells may be due to causes other than the transforming elements of the Ab-MuLV genome.

Abelson murine leukemia virus↗
PubMed1980

Characterization of multiple immunoglobulin mu-chains synthesized by two clones of a B cell lymphoma.

We have identified 3 species of mu-chain synthesized by mouse WEHI 279 lymphoma cells that differ in cellular location, size and charge--mui (internal), mum (membrane), and mus (secreted). Lactoperoxidase and galactose oxidase labeling experiments localize the mum chain to the plasma membrane and the mui chain to the cytoplasm. Pulse-chase experiments demonstrate that the mui pool contains precursors to both mum and mus chains. Comparative peptide mapping studies and cell labeling in the presence of tunicamycin suggest that the mum chain is 2000 daltons larger than the mus chains and that the difference is due to polypeptide alterations rather than carbohydrate differences. The WEHI 279 lymphoma has differentiated while in culture to a more advanced stage in the pathway of B cell differentiation.

Animals↗
PubMed1979

Assembly and secretion of pentameric IgM in a fusion between a nonsecreting B cell lymphoma and an IgG-secreting plasmacytoma.

A new immunoglobulin product has been obtained by hybridization of mouse cell lines arrested at different stages in B lymphocyte development. One line was shown to have the characteristics of an undifferentiated B cell that synthesizes monomeric IgM as a membrane receptor but does not express J chain. The second line was represent of a fully differentiated plasma cell synthesizing large amounts of IgG and J chain, but no IgM. Fusion of the two cell types yielded independent hybrid clones that secreted pentameric IgM, normally the first product of antigen-driven B cell differentiation. Analyses of the hybrid cells indicated that the IgM was expressed as a result of complementation between the synthetic capacities of the parental lines. The hybrid cells synthesized both monomeric IgM and J chain and assembled these components into a pentameric molecule with the expected stoichiometry of one J chain per five monomeric units. These findings provided further evidence that the induction of B cell differentiation includes a signal for de novo synthesis of the J chain. Moreover, the complementation achieved by this hybridization provides a system for identifying other intracellular events in B cell differentiation to IgM secretion.

Animals↗
PubMed1979

Differentiation antigens on normal and Abelson virus transformed lymphocytes.

Rabbit antisera to Abelson leukemia virus (A-MuLV)-induced murine lymphomas have been analyzed by absorption with a variety of murine lymphoma lines. Antibody binding to a panel of cell lines and normal lymphocytes was visualized by using hapten-sandwich indirect membrane immunofluorescence. Novel membrane antigens thereby detected are shared between lymphosarcomas, B lymphomas, normal B lymphocytes, and normal membrane immunoglobulin negative (sIg-) bone marrow cells, but are not found on T cells, thymic lymphomas, plasmacytoid lymphomas, or myelomas. The existence of such shared differentiation antigens suggests that sIg- A-MuLV-induced lymphosarcomas may be transformed B cell precursors. Since differences in the expression of these antigens on individual plasma-cytoid lymphoma lines were found, this category of lymphomas may include cells at a variety of differentiation states.

Alleles↗
PubMed1975

Oncogenic transformation of murine lymphoid cells by in vitro infection with Abelson leukemia virus.

Spleen cell cultures stimulated to DNA synthesis by antigen or mitogen were infected with Abelson virus, a C-type RNA virus inducing nonthymic lymphomas in mice. After 3 days the cells were transferred to mice and caused 100 percent incidence of lymphomas in as few as 29 days. That a number of the tumors were of donor origin, as shown by female karyotypes in recipient male mice, indicated that cells infected by virus in vitro were transformed. The process depended upon both virus and stimulation of lymphocytes in culture. Lymphoid tumors did not develop in mice receiving cells from virus-infected cultures not exposed to antigen or mitogen.

Animals↗
PubMed1974

Immunochemical analysis of the idiotypes of mouse myeloma proteins with specificity for levan or dextran.

This paper deals solely with idiotypic determinants, the configurations of which are modified when the antibody bearing them interacts with its ligand. This phenomenon is measured as an inhibition of the reaction between anti-idiotype and idiotype. Two points are made: (a) The assay for ligand-modifiable determinants can be used to determine the "size" of the combining site. This is illustrated here with the anti-alpha(1 --> 6) dextran mouse myeloma immunoglobulin W3129. Whether the interaction between a homologous series of alpha(1 --> 6) oligosaccharide ligands and the combining site of W3129 is measured by inhibition of precipitation with alpha(1 --> 6) dextran (4) or of binding of W3129 to anti-W3129 idiotype, the finding is the same. The order of inhibition is isomaltohexaose = isomaltopentaose >> isomaltotetraose > isomaltotriose >>> isomaltose. The combining site is optimally complementary to isomaltopentaose. (b) Cross-idiotypic specificity is closely correlated with cross-combining specificity; the converse is not true. This is illustrated here with three groups of mouse myeloma immunoglobulin, each specific for alpha(1 --> 3) dextran, alpha(1 -->6) dextran, beta(2 --> 1) or beta(2 --> 6) levan. If a given anti-idiotypic serum cross-reacted with several myeloma proteins, they always had similar combining specificity. Thus the three proteins, J558, MOPC 104E, and UPC 102, which cross-react with anti-J558 have combining specificity for alpha(1 --> 3) dextran; cross-reacting W3082, UPC 61, and Y5476 have specificity for levan; and cross-reacting W3129 and W3434 have specificity for alpha(1 --> 6) dextran. This extends previous studies with proteins specific for phosphorylcholine (7) or gamma-globulin (8). As expected, the converse is not true, for proteins may have combining specificity for alpha(1 --> 6) dextran e.g. QUPC 52, or levan e.g. J606, UPC 10 and yet not carry the above-mentioned reference idiotypes. The correlation between cross-idiotypic and combining specificity breaks down when idiotypic determinants which are not modifiable by ligand are studied. The implications of this are pointed out since most investigations deal with ligand-nonmodifiable determinants.

Animals↗
PubMed1974

Structure and immunochemistry of the cell wall mannans from Saccharomyces chevalieri, Saccharomyces italicus, Saccharomyces diastaticus, and Saccharomyces carlsbergensis.

The mannans of Saccharomyces chevalieri, S. italicus, S. diastaticus, and S. carlsbergensis, were acetolyzed, and the fragments were separated by gel filtration. All gave similar acetolysis fingerprints, which were distinguished from S. cerevisiae by the presence of a pentasaccharide component in addition to the mono-, di-, tri-, and tetrasaccharides. All oligosaccharide fragments were composed of mannose in alpha-linkage. From methylation analysis and other structural studies, the disaccharide was shown to be alphaMan(1 --> 2)Man; the trisaccharide was shown to be a mixture of alphaMan(1 --> 2)alphaMan (1 --> 2)Man and alphaMan(1 --> 3)alphaMan(1 --> 2)Man; the tetrasaccharide was alphaMan(1 --> 3)alphaMan(1 --> 2)alphaMan(1 --> 2)Man; and the pentasaccharide was alphaMan(1 --> 3)alphaMan(1 --> 3)alphaMan(1 --> 2)alphaMan(1 --> 2)Man. The ratios of the different fragments varied slightly from strain to strain. Mannanase digestion of two of the mannans yielded polysaccharide residues that were unbranched (1 --> 6)-linked polymers, thus establishing the structural relationship between these mannans and that from S. cerevisiae. Antisera raised against the various yeasts cross-reacted with the mannans from each, and also with S. cerevisae mannan. The mannotetraose and mannopentaose acetolysis fragments gave complete inhibition of the precipitin reactions, which indicated that, in these systems as in the S. cerevisiae system, the terminal alpha(1 --> 3)-linked mannose unit was the principal immunochemical determinant on the cell surface.

Antigens, Fungal↗