Evidence has accumulated to indicate that peripheral blood mononuclear cells (PBMC) incubated with lipopolysaccharide (LPS) stimulate synthesis or release of pyrogenic cytokines including interleukin-1␤ (IL-1␤), IL-6, and tumor necrosis factor-alpha (TNF-␣). These cytokines act targets in the periphery with generation of stimulatory signals directed to the brain [1,2]. Consequently, an excessive accumulation of prostaglandin E 2 inside the brain affects thermoregulatory centers in the hypothalamus and results in fever genesis.Other lines of evidence have shown that nuclear factor-B (NF-B) plays an important role in inflammatory responses through the regulation of genes encoding proinflammatory cytokines and inducible enzymes such as inducible nitric oxide synthase and cyclooxygenase [3][4][5]. The synthesis of cytokines, such as TNF-␣, IL-1␤, and IL-6, is mediated by NF-B. Japanese Journal of Physiology, 53, 367-375, 2003 Key words: rabbits, human peripheral blood mononuclear cells, cytokines, fever.Abstract: Lipopolysaccharide (LPS) stimulates peripheral mononuclear cells (PBMC) to synthesize or release pyrogenic cytokines, including interleukin-1␤ (IL-1␤), IL-6, and tumor necrosis factor-alpha (TNF-␣). Nuclear factor-kappa B (NF-B) influences inflammatory responses through the regulation of genes encoding cytokines. In the present study, experiments were carried out to determine whether an inhibition of NF-B mechanisms causes an inhibition of pyrogenic cytokine synthesis or release from PBMC and results in antipyresis. Intravenous administration of the supernatant fluids obtained from the human PBMC incubated with LPS caused feverlike hyperthermia in rabbits. The febrile responses were in parallel with the levels of IL-1␤, IL-6, and TNF-␣ in supernatant fluids. Both the fever and the increased levels of these cytokines in supernatant fluids were decreased by incubating LPS-PBMC with NF-B inhibitors, including pyrrolidine dithiocarbamate, sodium pyrithione, N-acetyl-cysteine, and curcumin. Moreover, an intravenous administration of LPS (0.5-2 g/kg) produced dose-dependent fever in the rabbits.The fevers were in parallel with the levels of IL-1␤, IL-6, and TNF-␣ in rabbit serum. A pretreatment of rabbits with an intravenous injection of pyrrolidine dithiocarbamate, sodium pryithione, N-acetyl-cysteine, or curcumin 1 h before the intravenous administration of LPS significantly attenuated the LPS-induced fever and/or increased levels of these cytokines in the serum of rabbits. Furthermore, pretreatment with an intravenous dose of anti-IL-1␤, anti-IL-6, or anti-TNF-␣ monoclonal antibody significantly attenuated the fever induced by the intravenous injection of LPS in rabbits. The antipyretic effects exerted by anti-L-1␤ monoclonal antibody were greater than those exerted by anti-L-6 or anti-NF-␣ monoclonal antibody. The data indicate that NF-B activation correlates with an LPS-induced synthesis or a release of cytokines (in particular, IL-1␤) from PBMC and triggers fever. Blocking NF-B mechanisms in the PBMC wit...

Abstract. Intravenous injection of the supernatant fluids from human peripheral blood mononuclear cells (PBMC) incubated with lipopolysaccharide (LPS) caused fever in rabbits. The fever was in parallel with the levels of either interleukin-1b (IL-1b), IL-6, or tumor necrosis factor-a (TNF-a ) in supernatant fluids. When incubating the platonin with the LPS-human PBMC, both the levels of IL-1b, IL-6, or TNF-a in supernatant fluids and the pyrogenicity of supernatant fluids were significantly suppressed. The febrile response to supernatant fluids from the LPSstimulated PBMC was attenuated almost completely by adding anti-IL-1b, but not anti-IL-6 or anti-TNF-a , monoclonal antibody to supernatant fluids. In addition, both the fever and the increased levels of either IL-1b, IL-6, or TNF-a in rabbit serum following an intravenous administration of LPS were significantly attenuated by pretreatment with an intravenous dose of platonin. Furthermore, the fever induced by intravenous injection of IL-1b was reduced by pretreatment of rabbits with intravenous injection of platonin. The data indicate that platonin inhibits production of pyrogenic cytokines (in particular, IL-1b) from PBMC and results in antipyresis.

These results suggest the anti-inflammatory activity of platonin is a result of reduced NF-kappaB activity due to inhibition of Akt and IKKbeta.

It has been shown that staphylococcal enterotoxin A (SEA) acts through human peripheral blood mononuclear cells (PBMC) to stimulate synthesis or release of pyrogenic cytokines. Nuclear factor-kappa B (NF-kappaB) is thought to play an important role in inflammatory responses through the regulation of genes encoding pro-inflammatory cytokines. The purpose of the present study was to determine whether the NF-kappaB mechanisms in human PBMC are involved in SEA-induced fever. Western blot evaluation revealed SEA was able to induce nuclear translocation of NF-kappaB from cytosol to nucleus in PBMC, which could be abolished by a NF-kappaB inhibitor such as pyrrolidine dithiocarbamate (PDTC), sodium pyrithione (Pyri), N-acetyl-L-cysteine (NAC), or curcumin (Cur). Electrophoretic mobility shift assay also showed that the NF-kappaB DNA-binding activity was increased in the SEA-treated PBMC. Again, the SEA-induced increased NF-kappaB binding activity was significantly attenuated by either PDTC, Pyri, NAC or Cur. The pyrogenic responses to supernatant fluids obtained from human PBMC stimulated with SEA were associated with increased levels of interleukin 1-beta (IL-1beta), IL-6, and tumor necrosis factor-alpha (TNF-alpha) in the supernatant fluids. Both the fever and the increased levels of IL-1beta, IL-6, and TNF-alpha in supernatant fluids obtained from the SEA-stimulated PBMC were decreased by incubating SEA-PBMC with either PDTC, Pyri, NAC, or Cur. Furthermore, the fever induced by systemic or central administration of SEA in rabbits were attenuated by pre-treatment with an systemic or central dose of either PDTC, Pyri, NAC, or Cur. The data indicate that inhibition of NF-kappaB prevents SEA-induced fever.