Etanercept-treated Mice Research Articles

Effect of TNFα blockade on UVB-induced inflammatory cell migration and collagen loss in mice

UVB irradiation induces pro-inflammatory cytokines including interleukin-1 (IL-1) and tumor necrosis factor-α (TNFα) in the skin. TNFα stimulates the chemotaxis of inflammatory cells to the skin. These cells secrete metalloproteinases (MMPs) and other enzymes that damage the cutaneous matrix. Therefore, blocking TNFα activity could be effective in preventing the influx of inflammatory cells and subsequent collagen degradation in the skin. In addition, TNFα downregulates procollagen mRNA, and thus blockade may be beneficial to production of type I collagen. Female C57BL/6 J mice were treated with etanercept (TNFα blocker, 4 mg/kg/day) for 4 days 1 h prior to UVB irradiation (100 mJ/cm2/day for 5 days). On the 5th day mice were sacrificed 3 h after UVB exposure. Blocking TNFα significantly inhibited UVB-induced recruitment of macrophages, mast cells, and neutrophils. UVB-irradiated mice skin contained more mature collagen compared to etanercept and UVB + etanercept-treated mice. Skin from UVB + etanercept-treated mice had more collagen fragments relative to UVB-irradiated mice. Procollagen protein was lower in UVB-irradiated and UVB + etanercept-treated mice. TNFα blockade decreased decorin and TGF-β1 in UVB-irradiated mice compared to UVB alone. MMP13 was inhibited by etanercept in UVB-irradiated mice (p < 0.01). In conclusion, blockade of TNFα significantly decreased mature collagen in UVB-irradiated mice, while increasing collagen fragmentation and decreasing procollagen.

Blockade of Tumor Necrosis Factor by Etanercept Prevents Postoperative Adhesion Formation in Mice.

Although adhesion formation is a frequent adverse event following intraperitoneal surgery, efficient prophylactic interventions have not yet been established. We recently reported that blockade of interleukin (IL)-6 prevented postoperative adhesion after cecum cauterization. Intriguingly, this intervention dampened tumor necrosis factor (TNF) induction in the injured serosa. Herein, we addressed whether TNF might be a key target and, if so, how TNF blockade rescued adhesion formation. Mice were administered an anti-TNF biologic (etanercept) on days -2 and -1 before and upon cecal cauterization. The adhesion scores were evaluated at day 7 postoperatively. Histological alterations were examined by immunochemistry/immunofluorescence studies. We incubated human neutrophils and mesothelial cell line cells with recombinant TNF in the presence of etanercept and measured transcript levels of cytokines and chemokines by quantitative reverse transcription-polymerase chain reaction (RT-qPCR). Etanercept rescued mice from adhesion formation, accompanied by a robust reduction of neutrophilia in the injured serosa. Immunofluorescence revealed a substantial formation of neutrophil extracellular traps (NETs) with the potential to induce tissue damage and profibrotic responses. In contrast, the etanercept-treated mice lacked NET formation. In addition, etanercept inhibited TNF-induced IL-6, TNF, and neutrophil-recruiting chemokines in neutrophils and mesothelial cells, a major cellular source of myofibroblasts in the adhesion band. Prophylactic administration of etanercept might be a potential strategy for preventing postoperative adhesion formation.

Alteration of the gut microbiota in tumor necrosis factor-α antagonist-treated collagen-induced arthritis mice.

Gut microbiota play an important role in rheumatoid arthritis (RA). Biological therapies targeting tumor necrosis factor-α (TNF-α) have been used for treatment in RA patients. However, whether TNF-α antagonist has some influence on gut microbiota is still unknown. This study aims to investigate the distribution of gut microbiota in collagen-induced arthritis (CIA) mice treated with the TNF-α antagonist etanercept. Collagen-induced arthritis mice were induced by type II collagen. Cytokine expression was detected by real-time polymerase chain reaction. 16S ribosomal RNA sequencing was performed to characterize the gut microbiota in CIA mice treated with vehicle or etanercept. Sequencing reads were processed by Microbial Ecology software program. Compared with vehicle-treated mice, we showed that CIA mice treated with etanercept led to attenuation of inflammation and reduced expression of TNF-α, interferon (IFN)-γ, interleukin (IL)-6 and IL-21. Meanwhile, results showed operational taxonomic units, richness estimators and the diversity indices of gut microbiota in etanercept-treated mice were lower than that in vehicle-treated mice. Moreover, bacterial abundance analyses showed that genus Escherichia/Shigella was more abundant in etanercept-treated mice, and Lactobacillus, Clostridium XlVa, Tannerella were less abundant. The altered bacterial genus was correlated with TNF-α, IFN-γ, IL-6, IL-21 and IL-10. Our results revealed that TNF-α antagonist treatment can reduce the abundance and diversity of gut microbiota in CIA mice. Targeted gut microbiota may be a new therapeutic strategy for the treatment of RA.

A novel fusion protein attenuates collagen–induced arthritis by targeting interleukin 17A and tumor necrosis factor α

This study was undertaken to generate a novel dual targeting fusion protein (DTF), targeting tumor necrosis factor α (TNF-α) and interleukin 17A (IL-17A), and determine its anti-arthritis properties in vitro and in vivo. DTF consisted of an anti-IL-17A single chain variable fragment, a soluble TNF receptor 1, and an Fc fragment. Both clinical and histopathological evaluations suggest that DTF and etanercept can ameliorate collagen induced arthritis. However, the arthritis severity score of DTF-treated mice was lower than that of etanercept-treated mice. In addition, DTF was more potent than etanercept in decreasing the ratio of RANKL/OPG in the serum and rebalancing the population ratio of Treg/Th17 cells in the spleens. In vitro, IL-17A and TNF-α had synergistic effects in inducing the expression of inflammatory cytokines in fibroblast-like synoviocyte from RA patients (RA-FLS), human leukemia (THP-1), and rheumatoid synovial fibroblast (MH7A). IL-17A and TNF-α also had synergistic effects in inducing proliferation and migration of MH7A cells. However, we observed that DTF was more efficient than etanercept in suppressing these synergistic effects. Our results demonstrate that DTF is highly efficient in the treatment of arthritis and has the potential to overcome the limited therapeutic responses obtained with single cytokine neutralization.

Tumor Necrosis Factor-Alpha Targeting Can Protect against Arthritis with Low Sensitization to Infection.

Tumor necrosis factor-alpha (TNF-α) blockade is an effective treatment for rheumatoid arthritis (RA) and other inflammatory diseases, but in patients, it is associated with reduced resistance to the infectious agents Mycobacterium tuberculosis and Listeria monocytogenes, among others. Our goal was to model infection and arthritis in mice and to compare etanercept, a currently used anti-TNF-α inhibitor, to an anti-TNF-α vaccine. We developed a murine surrogate of the TNF-α kinoid and produced an anti-murine TNF-α vaccine (TNFKi) composed of keyhole limpet hemocyanin conjugated to TNF-α, which resulted in anti-TNF-α antibody production in mice. We also used etanercept (a soluble receptor of TNF commonly used to treat RA) as a control of TNF neutralization. In a mouse model of collagen-induced arthritis, TNFKi protected against inflammation similar to etanercept. In a mouse model of acute L. monocytogenes infection, all TNFKi-treated mice showed cleared bacterial infection and survived, whereas etanercept-treated mice showed large liver granulomas and quickly died. Moreover, TNFKi mice infected with the virulent H37Rv M. tuberculosis showed resistance to infection, in contrast with etanercept-treated mice or controls. Depending on the TNF-α blockade strategy, treating arthritis with a TNF-α inhibitor could result in a different profile of infection suceptibility. Our TNFKi vaccine allowed for a better remaining host defense than did etanercept.

757 A possible role for M2 macrophages in preservation of dermal collagen during UVB exposure

We previously reported that giving anti-TNFα antibodies (etanercept) to mice blocks UVB recruitment of neutrophils and macrophages into the dermis, but paradoxically, etanercept accelerates UVB-induced loss of dermal collagen. To examine an unsuspected role for neutrophils or macrophages in dermal collagen preservation during UVB exposure, we performed neutrophil depletion and quantification of macrophage subtypes. Of note, M2 macrophages are involved in tissue remodeling in other circumstances and produce TGFβ, an inducer of procollagen. C57BL/6J mice were treated with either murine etanercept (4mg/kg/d) or an anti-Ly6G-specific monoclonal antibody (400μg/d to deplete neutrophils) for 7 days i.p, beginning 2 days before UVB exposure. Mice were irradiated with UVB (100 mJ/cm2/d for 5 d) or sham-irradiated. Skin was stained for neutrophils, M2 macrophages, TGFβ by IHC, and collagen fibers using picrosirius red. Under circular polarized light, picrosirius red differentiates collagen fibers as red or yellow (mature thick type I fibers) versus green (thin type III fibers). Our data show that in UVB-irradiated mice red fibers were decreased compared with sham-irradiated controls. In UVB+etanercept-treated mice, red fibers were markedly decreased compared to UVB without etanercept (p=0.001). Neutrophil-depleted UVB-treated mice showed more red fibers relative to UVB+etanercept-treated mice (p=0.01) and were similar to that seen with sham-irradiated mice. We show that blocking TNFα significantly inhibited M2 macrophage recruitment and TGFβ accumulation in UVB-irradiated mice (p=0.01). Neutrophil depletion in UVB-treated mice did not inhibit M2 macrophage recruitment or TGFβ staining relative to UVB alone. In conclusion etanercept inhibits recruitment of M2 macrophages into skin, as well as TGFβ production, coinciding with decreased mature collagen in the dermis of UVB+etanercept–treated mice relative to neutrophil-depleted UVB-treated mice. Future studies will examine the effects of macrophage depletion on mature collagen in UV-irradiated murine models.

Inhibition of Inflammation-Associated Olfactory Loss by Etanercept in an Inducible Olfactory Inflammation Mouse Model.

To determine the effect of a soluble human tumor necrosis factor alpha (TNF-α) receptor blocker (etanercept) on an inducible olfactory inflammation (IOI) mouse model. An in vivo study using a transgenic mouse model. Research laboratory. To study the impact of chronic inflammation on the olfactory system, a transgenic mouse model of chronic rhinosinusitis-associated olfactory loss was utilized (IOI mouse), expressing TNF-α in a temporally controlled fashion within the olfactory epithelium. In one group of mice (n = 4), etanercept was injected intraperitoneally (100 μg/dose, 3 times/week) concurrent with a 2-week period of TNF-α expression. A second group of mice (n = 2) underwent induction of TNF-α expression for 8 weeks, with etanercept treatment administered during the final 2 weeks of inflammation. Olfactory function was assayed by elecro-olfactogram (EOG), and olfactory tissue was processed for histology and immunohistochemical staining. Each group was compared with an equal-number control group. Compared with nontreated IOI mice, etanercept-treated IOI mice showed significantly improved EOG responses after 2 weeks (P < .001). After 8 weeks of induced inflammation, there was massive loss of olfactory epithelium and no EOG response in nontreated IOI mice. However, in etanercept-treated mice, regeneration of olfactory epithelium was observed. Concomitant administration of etanercept in IOI mice results in interruption of TNF-α-induced olfactory loss and induction of neuroepithelial regeneration. This demonstrates that etanercept has potential utility as a tool for elucidating the role of TNF-α in other olfactory inflammation models.

Blocking Tumor Necrosis Factor α Enhances CD8 T-cell-Dependent Immunity in Experimental Melanoma.

TNF plays a dual, still enigmatic role in melanoma, either acting as a cytotoxic cytokine or favoring a tumorigenic inflammatory microenvironment. Herein, the tumor growth of melanoma cell lines expressing major histocompatibility complex class I molecules at high levels (MHC-I(high)) was dramatically impaired in TNF-deficient mice, and this was associated with enhanced tumor-infiltrating CD8(+) T lymphocytes. Immunodepletion of CD8 T cells fully restored melanoma growth in TNF(-/-) mice. Systemic administration of Etanercept inhibited MHC-I(high) melanoma growth in immunocompetent but not in immunodeficient (IFNγ(-/-), nude, or CD8(-/-)) mice. MHC-I(high) melanoma growth was also reduced in mice lacking TNF-R1, but not TNF-R2. TNF(-/-) and TNF-R1(-/-) mice as well as Etanercept-treated WT mice displayed enhanced intratumor content of high endothelial venules surrounded by high CD8(+) T-cell density. Adoptive transfer of activated TNF-R1-deficient or -proficient CD8(+) T cells in CD8-deficient mice bearing B16K1 tumors demonstrated that TNF-R1 deficiency facilitates the accumulation of live CD8(+) T cells into the tumors. Moreover, in vitro experiments indicated that TNF triggered activated CD8(+) T cell death in a TNF-R1-dependent manner, likely limiting the accumulation of tumor-infiltrating CD8(+) T cells in TNF/TNF-R1-proficient animals. Collectively, our observations indicate that TNF-R1-dependent TNF signaling impairs tumor-infiltrating CD8(+) T-cell accumulation and may serve as a putative target to favor CD8(+) T-cell-dependent immune response in melanoma.

Etanercept restores normal insulin signal transduction in β2-adrenergic receptor knockout mice.

BackgroundInhibition of TNFα protects the retina against diabetic-like changes in rodent models. The mechanism by which TNFα induces deleterious retinal changes is not known. Previously, we have shown that TNFα can inhibit normal insulin signal transduction, leading to increased apoptosis in both retinal endothelial cells (REC) and Müller cells. Additionally, β2-adrenergic receptor knockout mice (β2KO) have increased TNFα levels and decreased insulin receptor activity. In this study, we hypothesized that inhibition of TNFα in β2KO mice would increase normal insulin signaling, leading to improved retinal function.MethodsC57BL6 or β2KO mice were left untreated or treated with etanercept (0.3 mg/kg subcutaneously, 3× a week) for 2 months. Electroretinogram analyses were done before treatment was initiated and after two months of treatment with etanercept on all mice. Western blot or ELISA analyses were done on whole retinal lysates from all four groups of mice for TNFα, suppressor of cytokine signaling 3 (SOCS3), insulin receptor, and apoptotic proteins.ResultsEtanercept significantly reduced TNFα levels in β2KO mice, leading to increased insulin receptor phosphorylation on tyrosine 1150/1151. SOCS3 levels were increased in β2KO mice, which were reduced after etanercept treatment. Pro-apoptotic proteins were reduced in etanercept-treated β2KO mice. Etanercept improved ERG amplitudes in β2KO mice.ConclusionsInhibition of TNFα by etanercept protects the retina likely through reduced TNFα-mediated insulin resistance, leading to reduced apoptosis.

Etanercept administration to neonatal SH3BP2 knock-in cherubism mice prevents TNF-α-induced inflammation and bone loss.

Cherubism is a genetic disorder of the craniofacial skeleton caused by gain-of-function mutations in the signaling adaptor protein, SH3-domain binding protein 2 (SH3BP2). In a knock-in mouse model for cherubism, we previously demonstrated that homozygous mutant mice develop T/B cell-independent systemic macrophage inflammation leading to bone erosion and joint destruction. Homozygous mice develop multiostotic bone lesions whereas cherubism lesions in humans are limited to jawbones. We identified a critical role of tumor necrosis factor α (TNF-α) in the development of autoinflammation by creating homozygous TNF-α-deficient cherubism mutants, in which systemic inflammation and bone destruction were rescued. In this study, we examined whether postnatal administration of an anti-TNF-α antagonist can prevent or ameliorate the disease progression in cherubism mice. Neonatal homozygous mutants, in which active inflammation has not yet developed, were treated with a high dose of etanercept (25 mg/kg, twice/week) for 7 weeks. Etanercept-treated neonatal mice showed strong rescue of facial swelling and bone loss in jaws and calvariae. Destruction of joints was fully rescued in the high-dose group. Moreover, the high-dose treatment group showed a significant decrease in lung and liver inflammatory lesions. However, inflammation and bone loss, which were successfully treated by etanercept administration, recurred after etanercept discontinuation. No significant effect was observed in low-dose-treated (0.5 mg/kg, twice/week) and vehicle-treated groups. In contrast, when 10-week-old cherubism mice with fully active inflammation were treated with etanercept for 7 weeks, even the high-dose administration did not decrease bone loss or lung or liver inflammation. Taken together, the results suggest that anti-TNF-α therapy may be effective in young cherubism patients, if treated before the inflammatory phase or bone resorption occurs. Therefore, early genetic diagnosis and early treatment with anti-TNF-α antagonists may be able to prevent or ameliorate cherubism, especially in patients with a mutation in SH3BP2.

TNF-α Inhibitors Attenuate Neuropeptide Y (NPY) Expression in the Murine Enteric Nervous System: Implications in Inflammation and Colonic Motility

Neuropeptide Y (NPY) is a small peptide neurotransmitter produced by the enteric neurons. We have demonstrated that NPY is upregulated in the murine enteric nervous system (ENS) during experimental colitis and that NPY knockout mice are resistant to experimental colitis. However the mechanism of NPY up regulation in the ENS, and its downstream impact on colonic motility are unknown. We investigated whether TNF-α inhibitor, Etanercept, can regulate NPY expression and colonic motility. We utilized an enteric neuronal cell line developed in our laboratory and dextran sodium sulfate mouse model of colitis to study NPY expression as modulated by TNF-α. NPY expression in human colonic biopsies was assessed by real time PCR. Colonic motility was assessed in using isometric muscle recording in isolated circular muscle strips with intact innervation. Neuronal apoptosis was evaluated by cleaved caspase-3 immunostaining. Neuronal nitric oxide synthase containing neurons (nNOS) were quantified by Diaphorase staining. NPY expression was upregulated in human IBD, and IBD colons displayed increased neuronal apoptosis and impaired motility. Etanercept attenuated NPY expression in vitro and in vivo. Etanercept-treated mice exhibited attenuated inflammation and reduction in neuronal apoptosis. There was restoration of nNOS neurons in DSS mice treated with Etanercept, which was evidenced by the reduction in pellet frequency and water content (diarrhea phenotype typical of IBD). Our data establish the significance of NPY-TNF-α interactions in IBD. Motility disorders persist in IBD patients even after the resolution of inflammation; hence it is compelling to further explore the role of TNF-α inhibitors in modulating motility issues associated with inflammatory disorders.

Inflammatory Cascades Driven by Tumor Necrosis Factor-Alpha Play a Major Role in the Progression of Acute Liver Failure and Its Neurological Complications

Background/aimsAcute liver failure (ALF) due to ischemic or toxic liver injury is a clinical condition that results from massive loss of hepatocytes and may lead to hepatic encephalopathy (HE), a serious neuropsychiatric complication. Although increased expression of tumor necrosis factor-alpha (TNF-α) in liver, plasma and brain has been observed, conflicting results exist concerning its roles in drug-induced liver injury and on the progression of HE. The present study aimed to investigate the therapeutic value of etanercept, a TNF-α neutralizing molecule, on the progression of liver injury and HE in mice with ALF resulting from azoxymethane (AOM) hepatotoxicity.Methods/Principal FindingsMice were administered saline or etanercept (10 mg/kg; i.p.) 30 minutes prior to, or up to 6 h after AOM. Etanercept-treated ALF mice were sacrificed in parallel with vehicle-treated comatose ALF mice and controls. AOM induced severe hepatic necrosis, leading to HE, and etanercept administered prior or up to 3 h after AOM significantly delayed the onset of coma stages of HE. Etanercept pretreatment attenuated AOM-induced liver injury, as assessed by histological examination, plasma ammonia and transaminase levels, and by hepatic glutathione content. Peripheral inflammation was significantly reduced by etanercept as shown by decreased plasma IL-6 (4.1-fold; p<0.001) and CD40L levels (3.7-fold; p<0.001) compared to saline-treated ALF mice. Etanercept also decreased IL-6 levels in brain (1.2-fold; p<0.05), attenuated microglial activation (assessed by OX-42 immunoreactivity), and increased brain glutathione concentrations.ConclusionsThese results indicate that systemic sequestration of TNF-α attenuates both peripheral and cerebral inflammation leading to delayed progression of liver disease and HE in mice with ALF due to toxic liver injury. These results suggest that etanercept may provide a novel therapeutic approach for the management of ALF patients awaiting liver transplantation.

Effect of Blockade of Tumor Necrosis Factor-α with Etanercept on Surgical Wound Healing in SWISS-OF1 Mice

To assess whether blockade of tumor necrosis factor-alpha (TNF-alpha) influences surgical wound healing in a normal mouse experimental model. Wound healing time course and degree of surgical wound collagenization were measured by morphological techniques and digital image analysis in 80 male SWISS-OF1 mice (40 received subcutaneous etanercept at a dose of 0.1 mg/25 g/ at -7, 0, 7, and 14 days). No significant differences were observed between treated and untreated animals in wound healing, re-epithelialization, or formation of inflammatory infiltrate or granulation tissue at days 7, 15, or 20 after surgery. At 20 days, the collagen area was larger in treated versus untreated mice (109,029 +/- 28,489 microm(2) vs 79,305 +/- 19,798 microm(2), p = 0.026, Mann-Whitney U test). Surgical wounds showed a higher degree of collagenization at 20 days in etanercept-treated versus untreated mice, with no differences in the time course of wound healing. These data suggest that biological therapies to block TNF-alpha do not affect wound healing and do not need to be suspended during the perioperative period.

ETANERCEPT ATTENUATES THE DEVELOPMENT OF CERULEIN-INDUCED ACUTE PANCREATITIS IN MICE

TNF-alpha plays a pivotal role in the pathogenesis of acute pancreatitis. Recent studies have shown that TNF-alpha inhibition significantly ameliorates the course of experimental acute pancreatitis, but in this context, the effects of Etanercept, a novel anti-TNF-alpha agent, have not been investigated so far. The aims of the present study are (i) to assess the effects of pharmacological inhibition of TNF-alpha by means of Etanercept on the inflammatory response and apoptosis in a murine model of necrotizing acute pancreatitis and (ii) to compare the results to those observed in TNF-alpha receptor 1 knockout (TNFR1-KO) mice. Necrotizing acute pancreatitis was induced in TNF-alpha wild type for TNFR1 (WT) and TNFR1-KO mice by intraperitoneal injection of cerulein (hourly x5, 50 microg/kg). In another group of WT mice, Etanercept was administered (5 or 10 mg/kg, s.c.) at 1 h after first cerulein injection. Control groups received saline treatment. After 24 h, biochemical, histological, and immunohistochemical evidences of acute pancreatitis developed in all cerulein-treated mice; apoptosis was also present in the pancreas. Contrarily, pancreatitis histological features, amylase and lipase levels, pancreas water content, and myeloperoxidase activity were reduced in a similar degree in Etanercept-treated and TNFR1-KO mice. Likewise, in these two groups, immunohistochemical stainings and terminal deoxynucleotidyltransferase-mediated UTP nick-end labeling assay were found negative. TNF-alpha receptor 1 gene deletion and Etanercept administration ameliorate the course of experimental acute pancreatitis in a similar degree. Future studies on clinical applications of Etanercept in pancreatitis seem promising.

Attenuation of murine collagen-induced arthritis by a novel, potent, selective small molecule inhibitor of IkappaB Kinase 2, TPCA-1 (2-[(aminocarbonyl)amino]-5-(4-fluorophenyl)-3-thiophenecarboxamide), occurs via reduction of proinflammatory cytokines and antigen-induced T cell Proliferation.

Demonstration that IkappaB kinase 2 (IKK-2) plays a pivotal role in the nuclear factor-kappaB-regulated production of proinflammatory molecules by stimuli such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 suggests that inhibition of IKK-2 may be beneficial in the treatment of rheumatoid arthritis. In the present study, we demonstrate that a novel, potent (IC(50) = 17.9 nM), and selective inhibitor of human IKK-2, 2-[(aminocarbonyl)amino]-5-(4-fluorophenyl)-3-thiophenecarboxamide (TPCA-1), inhibits lipopolysaccharide-induced human monocyte production of TNF-alpha, IL-6, and IL-8 with an IC(50) = 170 to 320 nM. Prophylactic administration of TPCA-1 at 3, 10, or 20 mg/kg, i.p., b.i.d., resulted in a dose-dependent reduction in the severity of murine collagen-induced arthritis (CIA). The significantly reduced disease severity and delay of disease onset resulting from administration of TPCA-1 at 10 mg/kg, i.p., b.i.d. were comparable to the effects of the antirheumatic drug, etanercept, when administered prophylactically at 4 mg/kg, i.p., every other day. Nuclear localization of p65, as well as levels of IL-1beta, IL-6, TNF-alpha, and interferon-gamma, were significantly reduced in the paw tissue of TPCA-1- and etanercept-treated mice. In addition, administration of TPCA-1 in vivo resulted in significantly decreased collagen-induced T cell proliferation ex vivo. Therapeutic administration of TPCA-1 at 20 mg/kg, but not at 3 or 10 mg/kg, i.p., b.i.d., significantly reduced the severity of CIA, as did etanercept administration at 12.5 mg/kg, i.p., every other day. These results suggest that reduction of proinflammatory mediators and inhibition of antigen-induced T cell proliferation are mechanisms underlying the attenuation of CIA by the IKK-2 inhibitor, TPCA-1.