Differential effect of interferon-gamma injection on mitogenic responses in sympathetically denervated submaxillary lymph nodes of rats.
This study aimed to assess the effect of interferon (IFN)-gamma treatment on mitogenic responses in submaxillary lymph nodes in the presence or absence of local sympathetic nerves. Adult male rats were subjected to a unilateral superior cervical ganglionectomy and to a contralateral sham-operation. Seven days later, rats received five i.p. daily injections of human IFN-gamma (10(5) U.I./kg) or saline. On the day after the last injection, rats were killed at six different times throughout a 24-h cycle and the mitogenic effect of lipopolysaccharide (LPS) and concanavalin A (Con A) was assessed in single-cell suspensions of lymph nodes. In vehicle-treated rats, proliferation responses to LPS in innervated lymph nodes did not show time-of-day variations while those in denervated lymph nodes attained a maximum at 17:00 h. Following IFN-gamma administration, a promoting effect of LPS mitotic response was detected at 01:00 h at the innervated side only. As far as the mitogenic responses to Con A, proliferation in innervated lymph nodes of vehicle-treated controls attained a maximum at 09:00 h. Such a daily variation in response to Con A was not detectable at the denervated side. IFN-gamma treatment increased significantly Con A activity by promoting a greater mitogenic response at 01:00 h. Sympathetic denervation of lymph nodes brought about a shift in the maximum in number of cells per mg of lymph node from 21:00 to 13:00 h. After IFN-gamma treatment, maxima in cell number occurred at 05:00 h at both the innervated and denervated side. The results indicate that IFN-gamma effects in rat submaxillary lymph nodes are under substantial modulation by local sympathetic nerves.
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Departamento de Bioquímica y Biología Molecular III, Facultad de Medicina, Universidad Complutense, Madrid, Spain.
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Castrillón
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Cano
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Arce
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Cardinali
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D000818:Animals; D007371:Interferon-gamma / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008198:Lymph Nodes / Q000187:drug effects / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013363:Submandibular Gland / Q000187:drug effects / Q000276:immunology; D013562:Sympathectomy; D013564:Sympathetic Nervous System / Q000502:physiology*
D008070:Lipopolysaccharides; D007371:Interferon-gamma