NADPH diaphorase histochemistry detects inducible nitric oxide synthetase activity in the thymus of naive and staphylococcal enterotoxin B-stimulated mice.
Here we examined the changes in NADPH diaphorase (NADPHd) and inducible nitric oxide synthetase (iNOS) positivity in the medulla of the mouse thymus in response to treatment with the superantigen, Staphylococcal enterotoxin B (SEB). A few NADPHd+ and iNOS+ cells scattered in the medulla were detected in the thymi of naive mice. SEB induced the appearance of a large number of NADPHd+- and iNOS-immunoreactive cells in the thymic medulla. In the thymus of iNOS-deficient mice, a total absence of these NADPHd+ and iNOS+ medullary cells was found both under basal conditions and after SEB stimulation. With the NADPHd reaction, only endothelial staining was detected in the thymi of iNOS-deficient mice. Our data indicate that NADPHd+ cells in the thymic medulla express iNOS and that SEB induces iNOS expression in the mouse thymus.
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Division of Critical Care, Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
Haskó
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Salzman
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Szabó
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D000818:Animals; D004768:Enterotoxins / Q000494:pharmacology; D006651:Histocytochemistry / Q000379:methods*; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009252:NADPH Dehydrogenase / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D051381:Rats; D017208:Rats, Wistar; D018089:Superantigens / Q000494:pharmacology; D013950:Thymus Gland / Q000187:drug effects / Q000201:enzymology*
D004768:Enterotoxins; D018089:Superantigens; C031818:enterotoxin B, staphylococcal; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; C496318:Nos2 protein, rat; D009252:NADPH Dehydrogenase