title: An antipyretic role for interleukin-10 in LPS fever in mice.
abstract: Interleukin (IL)-10 inhibits the synthesis of proinflammatory cytokines implicated in fever, including IL-1beta, IL-6, and tumor necrosis factor (TNF)-alpha. We hypothesized that IL-10 functions as an antipyretic in the regulation of fevers to lipopolysaccharide (LPS) and turpentine. Body temperature was measured by biotelemetry. Swiss Webster (SW) mice treated with recombinant murine IL-10 were resistant to fever induced by a low dose of LPS (100 microgram/kg ip) and to the hypothermic and febrile effects of a high (septiclike) dose of LPS (2.5 mg/kg ip). IL-10 knockout mice developed an exacerbated and prolonged fever in response to a low dose of LPS (50 microgram/kg ip) compared with their wild-type counterparts. At 4 h after injection of the low dose of LPS, plasma levels of IL-6, but not TNF-alpha, were significantly elevated in the IL-10 knockout mice compared with their wild-type controls (ANOVA, P < 0.05). After injection of the same high dose of LPS injected into SW mice, wild-type mice developed a fever at 24 h whereas IL-10 knockout mice immediately developed a profound hypothermia that lasted through 41 h (ANOVA, P < 0.05). Body weight and food intake were more significantly depressed in response to the high dose of LPS in the knockout mice compared with their wild-type controls. Only 30% of the IL-10 knockout mice survived compared with 100% of the wild-type mice (Fisher's exact test, P < 0.05). Fever in response to the injection of turpentine (100 microliter/mouse sc) did not differ between wild-type and IL-10 knockout mice. These data support the hypotheses that 1) IL-10 functions as an endogenous antipyretic following exposure to LPS, 2) a putative mechanism of the early antipyretic action of IL-10 is through the inhibition of plasma levels of IL-6, 3) IL-10 has a protective role in the lethal effects of exposure to high levels of LPS, and 4) endogenous IL-10 does not have a role in fever induced by turpentine.
authors.affiliation: Lovelace Respiratory Research Institute, Albuquerque, New Mexico 87185, USA.
authors.forename: L R
authors.initials: LR
authors.lastname: Leon
authors.forename: W
authors.initials: W
authors.lastname: Kozak
authors.forename: K
authors.initials: K
authors.lastname: Rudolph
authors.forename: M J
authors.initials: MJ
authors.lastname: Kluger
mesh_terms: D018712:Analgesics, Non-Narcotic / Q000494:pharmacology*; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects; D005334:Fever / Q000503:physiopathology*; D016753:Interleukin-10 / Q000235:genetics / Q000494:pharmacology*; D015850:Interleukin-6 / Q000097:blood; D007509:Irritants; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout / Q000235:genetics; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D014425:Turpentine
chemical_list: D018712:Analgesics, Non-Narcotic; D015850:Interleukin-6; D007509:Irritants; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D014425:Turpentine