A number of Friend leukemia cell variants with a interferon-gamma (IFN-gamma)-resistant phenotype have been isolated. They appear resistant to the antiproliferative action of IFN-gamma and to the induction of the antiviral state assessed by Friend leukemia virus release and vesicular stomatitis virus yield. Selection was performed via a prolonged exposure to increasing amounts of highly purified recombinant IFN-gamma of wild-type Friend cells or of variant clones thereof already resistant to IFN-alpha/beta (Affabris et al., 1982, Virology 120, 441-452). Only the clones derived from IFN-alpha/beta-resistant variants showed a phenotype fully resistant to IFN-gamma treatment while keeping their previously acquired resistance to IFN-alpha/beta. These cells are not deficient in high-affinity receptors for IFN-gamma so that their resistant phenotype appears to be mediated by events distal to binding of IFN-gamma to its receptors. Furthermore, analysis of IFN-induced dsRNA-dependent 2-5A synthetase and 67K protein kinase enzymatic activities, biochemical markers for cellular responses to IFN, showed that both these activities were not induced in IFN-alpha/beta and IFN-gamma-resistant clones when treated with either type of IFN. Accordingly, no increased expression of 2-5A synthetase mRNA(s) could be detected by probing poly(A)+-enriched RNA from cells exposed to IFN-alpha/beta or IFN-gamma treatment with murine or human specific cDNAs. On the other hand, no major changes in restriction patterns of 2-5A synthetase gene(s) were observed in these variant cells by restriction endonuclease digestion and Southern blotting. In addition, analysis of 2-5A synthetase mRNA induction, performed on wild-type cells, showed that the kinetic of induction due to IFN-gamma treatment is slower than that obtained with IFN-alpha/beta.

COCCIA E.M., FEDERICO M., ROMEO G., AFFABRIS E, COFANO F., & ROSSI G.B (1988). Interferons-alpha,beta and gamma-resistant Friend cell variants exhibiting receptor sites for Interferons but no induction of 2-5A synthetase and 67K protein kinase. JOURNAL OF INTERFERON RESEARCH, 8(1), 113-127 [10.1089/jir.1988.8.113].

Interferons-alpha,beta and gamma-resistant Friend cell variants exhibiting receptor sites for Interferons but no induction of 2-5A synthetase and 67K protein kinase

AFFABRIS, Elisabetta;
1988

Abstract

A number of Friend leukemia cell variants with a interferon-gamma (IFN-gamma)-resistant phenotype have been isolated. They appear resistant to the antiproliferative action of IFN-gamma and to the induction of the antiviral state assessed by Friend leukemia virus release and vesicular stomatitis virus yield. Selection was performed via a prolonged exposure to increasing amounts of highly purified recombinant IFN-gamma of wild-type Friend cells or of variant clones thereof already resistant to IFN-alpha/beta (Affabris et al., 1982, Virology 120, 441-452). Only the clones derived from IFN-alpha/beta-resistant variants showed a phenotype fully resistant to IFN-gamma treatment while keeping their previously acquired resistance to IFN-alpha/beta. These cells are not deficient in high-affinity receptors for IFN-gamma so that their resistant phenotype appears to be mediated by events distal to binding of IFN-gamma to its receptors. Furthermore, analysis of IFN-induced dsRNA-dependent 2-5A synthetase and 67K protein kinase enzymatic activities, biochemical markers for cellular responses to IFN, showed that both these activities were not induced in IFN-alpha/beta and IFN-gamma-resistant clones when treated with either type of IFN. Accordingly, no increased expression of 2-5A synthetase mRNA(s) could be detected by probing poly(A)+-enriched RNA from cells exposed to IFN-alpha/beta or IFN-gamma treatment with murine or human specific cDNAs. On the other hand, no major changes in restriction patterns of 2-5A synthetase gene(s) were observed in these variant cells by restriction endonuclease digestion and Southern blotting. In addition, analysis of 2-5A synthetase mRNA induction, performed on wild-type cells, showed that the kinetic of induction due to IFN-gamma treatment is slower than that obtained with IFN-alpha/beta.
COCCIA E.M., FEDERICO M., ROMEO G., AFFABRIS E, COFANO F., & ROSSI G.B (1988). Interferons-alpha,beta and gamma-resistant Friend cell variants exhibiting receptor sites for Interferons but no induction of 2-5A synthetase and 67K protein kinase. JOURNAL OF INTERFERON RESEARCH, 8(1), 113-127 [10.1089/jir.1988.8.113].
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11590/135358
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