There is considerable evidence implicating tumor necrosis factor alpha (TNF-alpha) in the pathogenesis of rheumatoid arthritis. This evidence is based not only on the universal presence of TNF-alpha in arthritic joints accompanied by the upregulation of TNF-alpha receptors but also on the effects of neutralizing TNF-alpha in joint cell cultures. Thus, neutralization of TNF-alpha in vitro results in inhibition of the production of interleukin 1, which like TNF-alpha, is believed to contribute to joint inflammation and erosion. To determine the validity of this concept in vivo, the effect of administering TNF-neutralizing antibodies to mice with collagen-induced arthritis has been studied. This disease model was chosen because of its many immunological and pathological similarities to human rheumatoid arthritis. TN3-19.12, a hamster IgG1 monoclonal antibody to murine TNF-alpha/beta, was injected i.p. into mice either before the onset of arthritis or after the establishment of clinical disease. Anti-TNF administered prior to disease onset significantly reduced paw swelling and histological severity of arthritis without reducing the incidence of arthritis or the level of circulating anti-type II collagen IgG. More relevant to human disease was the capacity of the antibody to reduce the clinical score, paw swelling, and the histological severity of disease even when injected after the onset of clinical arthritis. These results have implications for possible modes of therapy of human arthritis.

Blazek et al. demonstrate that treatment with IL-28A reduces inflammation in collagen-induced arthritis by restricting the recruitment of IL-1β+ neutrophils.

It is hypothesized that the balance of cytokines produced by Th1/Th2 subsets of T helper cells plays an important role in the development of autoimmune diseases. Murine collagen-induced arthritis (CIA) is an example of an autoimmune disease in which immunization with cartilage-derived type II collagen induces, firstly, a T cell response to type II collagen and, secondly, the manifestation of a destructive inflammatory response in affected joints. We have investigated the role of Th1/Th2 responses in the development of CIA by monitoring levels of interferon (IFN)-gamma (a Th1 cytokine) and interleukin (IL)-4 and IL-10 (Th2 cytokines), and IL-1 beta and tumor necrosis factor (TNF) (pro-inflammatory cytokines) produced by cultured draining lymph node cells (LNC) from collagen-immunized DBA/1 mice during the induction phase of arthritis and throughout the time of clinical manifestation and subsequent remission of the disease. Although a transient increase in IL-10 was detected 3 days after immunization, Th2 cytokine production was found to be almost completely suppressed 6 days after immunization. In contrast, IFN-gamma was detected in LNC cultures as early as 6 days after immunization and the addition of type II collagen to the culture medium resulted in an approximately 10-fold increase in IFN-gamma production, indicating that a predominantly Th1 response had become established by this time. IFN-gamma production by LNC was found to be further increased at the time of clinical manifestation of arthritis and could be up-regulated by co-culture with type II collagen. IL-10 was not detected in LNC cultures at the onset of arthritis and IL-4, although present, was found to be markedly suppressed in LNC cultures containing type II collagen. These findings indicate that Th1 responses are predominant at the time of onset of arthritis and that the activation of collagen-specific Th1 cells may result in suppression of Th2 activity. IFN-gamma production declined progressively during the progression and subsequent remission of arthritis whereas levels of IL-10 increased and low, though persistent, levels of IL-4 were detected throughout this period. High levels of IL-1 beta and TNF-alpha production were detected at the onset of the disease. The role of Th1 responses in the development of CIA was further emphasized by the observation that immunization of mice with type II collagen in incomplete Freund's adjuvant, which normally fails to induce arthritis, resulted in a predominantly Th2 cytokine profile.

Collagen-induced arthritis is a well-validated, but strain-dependent mouse model of rheumatoid arthritis, with H-2(q) and H-2(r) strains showing the greatest degree of susceptibility. This protocol describes the induction of arthritis in the C57BL/6 strain (H-2(b)), which forms the genetic background of the majority of genetically modified strains. This protocol involves purification of type II collagen from chicken sternums, immunization of mice, clinical assessment of arthritis and analysis of T- and B-cell responses to type II collagen. Key aspects of the protocol are the need to use chicken collagen for immunization and the importance of avoiding aggressive behavior in males. The incidence of arthritis varies from 50 to 80% and is milder than the classical collagen-induced arthritis model. This procedure takes approximately 3 months to complete.

Abstract. In the mammalian host, the unicellular flagellate Trypanosoma brucei is covered by a dense surface coat that consists of a single species of macromolecule, the membrane form of the variant surface glycoprotein (mfVSG). After uptake by the insect vector, the tsetse fly, bloodstream-form trypanosomes differentiate to procyclic forms in the fly midgut.

We report here that joint inflammation in collagen-induced arthritis is more aggravated in CD44-knockout mice than in WT mice, and we provide evidence for molecular redundancy as a causal factor. Furthermore, we show that under the inflammatory cascade, RHAMM (receptor for hyaluronan-mediated motility), a hyaluronan receptor distinct from CD44, compensates for the loss of CD44 in binding hyaluronic acid, supporting cell migration, up-regulating genes involved with inflammation (as assessed by microarrays containing 13,000 cDNA clones), and exacerbating collagen-induced arthritis. Interestingly, we further found that the compensation for loss of the CD44 gene does not occur because of enhanced expression of the redundant gene (RHAMM), but rather because the loss of CD44 allows increased accumulation of the hyaluronic acid substrate, with which both CD44 and RHAMM engage, thus enabling augmented signaling through RHAMM. This model enlightens several aspects of molecular redundancy, which is widely discussed in many scientific circles, but the processes are still ill defined

Objective. There is a disparity in the animal models used to study pain in rheumatoid arthritis (RA), which tends to be acute in nature, and models used to assess the pathogenesis of RA. The latter models, like human RA, are lymphocyte-driven and polyarthritic. We assessed pain behavior and mechanisms in collageninduced arthritis (CIA), the model of preclinical arthritis used most commonly in the field of immunology. We then validated the model using anti-tumor necrosis factor (anti-TNF) therapy, which has analgesic effects in models of inflammation as well as in human RA.Methods. CIA was induced in DBA/1 mice by immunization with type II collagen at the base of the tail. Swelling and mechanical and thermal hyperalgesia were assessed before and for 28 days after the onset of arthritis. Spontaneous behavior was assessed using an automated activity monitor. Glial activity was assessed by glial fibrillary acidic protein expression, and nerve damage was evaluated by activating transcription factor 3 expression. The actions of anti-TNF therapy on nociception were then evaluated.Results. Arthritis resulted in a decrease in the threshold for thermal and mechanical stimuli, beginning on the day of onset. Decreased spontaneous activity was also observed. A significant increase in the number of hyperplasic spinal cord astrocytes was observed beginning 10 days after the onset of arthritis. Anti-TNF therapy was profoundly analgesic, with an efficacy similar to that of cyclooxygenase 2 inhibition, and reduced astrocyte activity in CIA.Conclusion. This study shows that the CIA model is suitable for testing not only antiinflammatory but also analgesic drugs for potential use in RA, and highlights the importance of using appropriate disease models to assess relevant pain pathways.

Objective. Interleukin-10 (IL-10) is a potent inhibitor of the proinflammatory cytokines, including tumor necrosis factor a and IL-1, which are considered important in the pathogenesis of rheumatoid arthritis (RA). The study was undertaken to establish whether IL-10 can ameliorate arthritis in the collagen-induced arthritis (CIA) model of RA.Methods. DBM1 mice were immunized with bovine type I1 collagen in adjuvant, and treated daily after disease onset with recombinant murine IL-10 or with saline as a control. Mice were monitored for paw swelling and clinical score. Histologic analysis was also performed.Results. IL-10 treatment of established CIA inhibited paw swelling (P < O.OOOl), as well as disease progression as defined by clinical score (P < 0.0002).Cartilage destruction, as assessed histologically, was reduced in IL-16treated mice compared with controls (P < 0.01).Conclusion. IL-10 suppresses established CIA, probably by inhibiting proinflammatory cytokine production. Our results, taken together with previously reported findings, indicate a potential therapeutic role for IL-10 in RA.