SUMMARYWe performed antigenic analysis of the haemagglutinin and neuraminidase subunits of a recombinant virus (A/swine/Kanagawa/2/78) isolated from a pig in Japan in 1978, using a series of monoclonal antibodies to H1 (Hswl) haemagglutinin and N2 neuraminidases of H2N2 and H3N2 viruses. Results obtained in haemagglutination inhibition tests with five monoclonal antibodies to the haemagglutinin of A/N J/8/76 (H1N1) revealed that the haemagglutinin of three H1N1 and the recombinant viruses were indistinguishable from that of A/N J/8/76. The neuraminidase of A/swine/Kanagawa/2/78 was found to be antigenically similar to A/Kumamoto/22/76 (H3N2, A/Victoria/3/75-1ike strain). The oligonucleotide maps of the entire RNAs of H 1N 1, H1N2 and H3N2 viruses showed that A/swine/Kanagawa/2/78 (HIN2) virus was more similar to swine (H1N1) virus than to A/Kumamoto/22/76 (H3N2) virus. Radioactive cDNA was prepared by reverse transcription of the recombinant virus RNA using a dodecadeoxyribonucleotide primer and used in DNA-RNA hybridization experiments. The results obtained in molecular hybridization based on blotting procedures showed that all cDNA segments except gene 6 hybridized efficiently with RNAs of swine (H 1N 1) influenza virus. The sixth cDNA segment was homologous to the corresponding RNA segment of H3N2 virus. The genetic relatedness of A/swine/Kanagawa/2/78 (H1N2) with either A/swine/Kanagawa/4/78 (HIN 1) or A/Kumamoto/22/76 (H3N2) was clearly established by hybridization between the cDNA segment probes and viral RNA. It was concluded that the neuraminidase gene of A/swine/Kanagawa/2/78 (H1N2) was derived from a human H3N2 virus, while the seven other genes were from a swine H1N1 virus.

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SummaryThe non-obese diabetic (NOD) mouse spontaneously develops autoimmune Type i (insulindependent) diabetes mellitus. NOD mice exhibit massive infiltrates of T cells and macrophages into pancreatic islets (insulitis) prior to diabetes. The contribution of oxygen free radicals to the development of insulitis in NOD mice was examined by administration of its scavengers, such as superoxide dismutase and catalase. Bovine superoxide dismutase and catalase were each coupled to polyethylene glycol. The treatment with superoxide dismutase-polyethylene glycol reduced the number of islets with insulitis and increased the undamaged islet tissue, as compared with the control group. The treatment with catalase-polyethylene glycol showed a similar tendency which did not reach significance. Using a flow cytometric assay of the oxidation of 2', 7'-dichlorofluorescein, the content of reactive oxygen intermediates in islet cells in the culture system was measured and the effect of peritoneal exudate cells and T cells on their production examined. Peritoneal exudate cells, but not T cells, from NOD mice increased the content of reactive oxygen intermediates in islet cells of either the NOD mouse or the ILI mouse (MHC-identical to NOD); the addition of snperoxide dismutase to the culture medium suppressed this increase in NOD or ILI islet cells. The present data support the concept that production of oxygen free radicals mediated by macrophages can damage islet beta cells, directly resulting in autoimmune Type i diabetes in NOD mice. [Diabetologia (1994) 37: 22-31] Key words NOD mice, insulitis, reactive oxygen intermediates, superoxide dismutase, peritoneal macrophages.Lymphoid cell infiltration into pancreatic islets (insulitis) is a well-recognized feature of Type i (insulindependent) diabetes mellitus both in humans [1] and in rodents with spontaneous diabetes [2,3]. The nonobese diabetic (NOD) mouse spontaneously develops an insulin-dependent diabetes. NOD mice exhibit massive infiltrates of lymphoid cells and macrophages into pancreatic islets (insulitis) prior to complete betacell destruction, and insulitis appears as early as 5 weeks of age. Makino and co-workers [4] have shown