Role of IL-10 in inflammation - Studies using cytokine knockout mice

Interleukin-10 (IL-10) inhibits the synthesis of proinflammatory cytokines known to be involved in fever, including IL-1, IL-6, and tumor necrosis factor-alpha. We hypothesized that IL-10 modulates lipopolysaccharide (LPS)-induced fever in mice. Body temperature was measured by biotelemetry. Swiss Webster mice injected with recombinant murine IL-10 (rmuIL-10) were resistant to fever induced by a low dose of LPS (100 mu g/kg, ip) and to the hypothermic and febrile effects of a high (septic-like) dose of LPS (2.5 mg/kg, ip). Injection of rmuIL-10 alone bad no effect on afebrile body temperature of swiss Webster mice. IL-10 knockout mice showed an exacerbated and prolonged fever in response to a low dose of LPS (50 mu g/kg, ip) compared to their wild-type counterparts. These data support the hypothesis that IL-10 acts as an endogenous cryogen during LPS-induced fever in mice.