Severe inflammatory arthritis and lymphadenopathy in the absence of TNF.

It has been postulated that TNF has a pivotal role in a cytokine cascade that results in joint inflammation and destruction in rheumatoid arthritis (RA). To evaluate this, we examined the response of TNF-deficient (Tnf(-/-)) mice in two models of RA. Collagen-induced arthritis (CIA) was induced by injection of chick type II collagen (CII) in CFA. Tnf(-/-) mice had some reduction in the clinical parameters of CIA and, on histology, significantly more normal joints. However, severe disease was evident in 54% of arthritic Tnf(-/-) joints. Tnf(-/-) mice had impaired Ig class switching, but preserved T cell proliferative responses to CII and enhanced IFN-gamma production. Interestingly, CII-immunized Tnf(-/-) mice developed lymphadenopathy and splenomegaly associated with increased memory CD4(+) T cells and activated lymph node B cells. Acute inflammatory arthritis was also reduced in Tnf(-/-) mice, although again some mice exhibited severe disease. We conclude that TNF is important but not essential for inflammatory arthritis; in each model, severe arthritis could proceed even in the complete absence of TNF. These results call into doubt the concept that TNF is obligatory for chronic autoimmune and acute inflammatory arthritis and provide a rationale for further studies into TNF-independent cytokine pathways in arthritis.     

Flk-1＋骨髓间充质干细胞移植上调白细胞介素6水平：是否同时加重了胶原诱导性关节炎小鼠的症状？

背景：间充质干细胞的免疫调节作用是被大家普遍认可的,在以往实验中也对Flk-1＋骨髓间充质干细胞体外抑制T/B淋巴细胞增殖的能力进行了确认。目的：验证Flk-1＋骨髓间充质干细胞对胶原诱导性关节炎小鼠的治疗作用。方法：健康10周龄雄性DBA-1（H-2Kq）小鼠18只,随机分为3组：初次免疫后细胞移植组、加强免疫后细胞移植组、模型对照组,3组小鼠均通过尾皮下注射牛Ⅱ型胶原进行初次免疫,21d后同法进行加强免疫,建立胶原诱导性关节炎模型。密度梯度离心法和贴壁筛选法体外分离DBA-1（H-2Kq）小鼠Flk-1＋骨髓间充质干细胞,初次免疫后细胞移植组小鼠在初次免疫后立即经尾静脉输注Flk-1＋骨髓间充质干细胞（1～2）×106个/只,加强免疫后细胞移植组小鼠在加强免疫时同法输注等量Flk-1＋骨髓间充质干细胞,模型对照组小鼠于初次免疫后0或21d尾静脉输注等量生理盐水。观察初次免疫后和加强免疫后各组小鼠的爪垫增厚情况、临床评分,检测小鼠关节病理学变化及血清因子质量浓度的动态变化。结果与结论：与模型对照组比较,初次免疫后细胞移植组爪垫增厚程度及平均临床疾病得分均无明显差异（P0.05）,均可见明显的滑膜组织损伤和炎症细胞浸润,各血清细胞因子质量浓度基本相似;而加强免疫后细胞移植组爪垫明显增厚（P0.01）,平均临床疾病得分高达3.35分,滑膜损伤严重,毛细血管增生,在初次免疫后28d白细胞介素6血清浓度急剧上升（P0.1）,初次免疫后35d白细胞介素6血清浓度又明显下降（P0.1）。提示在胶原诱导性关节炎小鼠模型中,Flk-1＋骨髓间充质干细胞移植不但未取得预期的治疗效果,还在加强免疫后细胞移植组观察到显著地关节炎症状恶化现象,其可能通过上调白细胞介素6血清浓度加重类风湿关节炎小鼠的行为症状。     

Enhancement of collagen-induced arthritis in mice by diesel exhaust particles.

The present study was undertaken to investigate the effect of diesel exhaust particles (DEP) on collagen-induced arthritis (CIA), which is an experimental model of autoimmune disease, in mice. CIA was induced by s.c. injection of type II collagen (CII) emulsified with complete Freund's adjuvant into the base of the tail (day 0) followed by a booster injection on day 21. Varying doses of DEP were intranasally administered every 2 days from days 0 to 20. The results showed that administration of DEP enhanced both the incidence and the severity of CIA. The enhancement of the disease was associated with pronounced production of anti-CII IgG and IgG2a antibodies. Treatment with DEP also augmented proliferative responses of spleen cells to CII. There was marked secretion of interferon-gamma, interleukin (IL)-2, and IL-4 from the lymphoid cells in DEP-treated mice. Administration of DEP after onset of CIA was also effective in enhancing the severity of the disease as well as production of anti-CII IgG and IgG2a antibodies and secretion of interferon-gamma, IL-2, and IL-4. These results suggest that exposure to DEP may influence autoimmune disease.     

Collagen II-pulsed antigen-presenting cells genetically modified to secrete IL-4 down-regulate collagen-induced arthritis

We explored the possibility that pulsed antigen-presenting cells (APC) provide a model vector system for site-specific delivery of immunosuppressive proteins during collagen-induced arthritis (CIA), an animal model for rheumatoid arthritis. Thus, mice were treated with either B cells or macrophages engineered to secrete IL-4 and loaded (or not) with type II collagen (CII). Systemic injection of an IL-4-producing B cell hybridoma resulted in a reduction of arthritis severity which was further improved when APC were incubated with CII before their transfer. Unmanipulated B cells loaded with CII also exerted a potent suppressive effect. Likely, clinical amelioration was observed in mice given at priming syngeneic bone marrow-derived macrophages producing IL-4 and pulsed with CII in comparison to the other groups. When the same dose of cells was transferred at disease onset, a moderate beneficial effect was observed. Whatever the APC inoculated, the beneficial effect did not rely upon an IL-4-driven shift towards Th2 phenotype. Systemic administration of fluorescent dye labeled macrophages to arthritic mice has shown that some of these cells rapidly migrate to joints. Moreover, IL-4 transfected macrophages retained their potent capacity to present CII peptides to T cells. These findings validate the use of CII peptide-loaded engineered APC as therapeutic vector cells in CIA and allow consideration of this strategy for the administration of various anti-inflammatory proteins.     

Effects of the bisphosphonate ibandronate on hyperalgesia,substance P,and cytokine levels in a rat model of persistent inflammatory pain

The anti‐inflammatory and analgesic properties of different bisphosphonates have been demonstrated in both animal and human studies. Ibandronate is a third‐generation bisphosphonate effective in managing different types of bone pain. In this study we investigated its effects in a standard pre‐clinical model of inflammatory pain. We evaluated the effects of a single injection of different doses (0.5, 1.0, and 2.0mg/kg i.p.) of ibandronate on inflammatory oedema and cutaneous hyperalgesia produced by the intraplantar injection of complete Freund's adjuvant (CFA) in the rat hind‐paw. In addition, we measured the effects of this drug (1.0mg/kg i.p.) on hind‐paw levels of different pro‐inflammatory mediators (PGE‐2, SP, TNF‐α, and IL‐1β). We also measured the levels of SP protein and of its mRNA in the ipsilateral dorsal root ganglia (DRG). Ibandronate proved able to reduce the inflammatory oedema, the hyperalgesia to mechanical stimulation, and the levels of SP in the inflamed tissue as measured 3 and 7 days following CFA‐injection. This drug significantly reduced the levels of TNF‐α and IL‐1β only on day 7. On the other hand, the levels of PGE‐2 in the inflamed hind‐paw were unaffected by the administration of this bisphosphonate. Finally, ibandronate blocked the overexpression of SP mRNA in DRG induced by CFA‐injection in the hind‐paw. These data help to complete the pharmacodynamic profile of ibandronate, while also suggesting an involvement of several inflammatory mediators, with special reference to substance P, in the analgesic action of this bisphosphonate.     

Chronic pain and genetic background interact and influence opioid analgesia, tolerance, and physical dependence

Opioids are commonly used in the treatment of moderate to severe pain. However, their chronic use is limited by analgesic tolerance and physical dependence. Few studies have examined how chronic pain affects the development of tolerance or dependence, and essentially no studies have looked at the role of both genetics and pain together. For these studies we used 12 strains of inbred mice. Groups of mice from each strain were tested at baseline for morphine analgesic sensitivity, mechanical nociceptive threshold, and thermal nociceptive threshold. Mice were then given morphine in a 4-day escalating morphine administration paradigm followed by reassessment of the morphine dose-response relationship. Finally, physical dependence was measured by administering naloxone. Parallel groups of mice underwent hind paw injection of complete Freund's adjuvant (CFA) to induce chronic hind paw inflammation 7 days prior to the beginning of testing. The data showed that CFA treatment tended to lower baseline ED(50) values for morphine and enhanced the degree of analgesic tolerance observed after 4 days of morphine treatment. In addition, the degree of jumping behavior indicative of physical dependence was often altered if mice had been treated with CFA. The influence of background strain was substantial for all traits measured. In silico haplotypic mapping of the tolerance and physical dependence data demonstrated that CFA pretreatment altered the pattern of the predicted associations and greatly reduced their statistical significance. We conclude that chronic inflammatory pain and genetics interact to modulate the analgesic potency of morphine, tolerance, and physical dependence.     

Antibodies against citrullinated proteins enhance tissue injury in experimental autoimmune arthritis

Antibodies against citrullinated proteins are specific and predictive markers for rheumatoid arthritis although the pathologic relevance of these antibodies remains unclear. To investigate the significance of these autoantibodies, collagen-induced arthritis (CIA) in mice was used to establish an animal model of antibody reactivity to citrullinated proteins. DBA/1J mice were immunized with bovine type II collagen (CII) at days 0 and 21, and serum was collected every 7 days for analysis. Antibodies against both CII and cyclic citrullinated peptide, one such citrullinated antigen, appeared early after immunization, before joint swelling was observed. Further, these antibodies demonstrated specific binding to citrullinated filaggrin in rat esophagus by indirect immunofluorescence and citrullinated fibrinogen by Western blot. To evaluate the role of immune responses to citrullinated proteins in CIA, mice were tolerized with a citrulline-containing peptide, followed by antigen challenge with CII. Tolerized mice demonstrated significantly reduced disease severity and incidence compared with controls. We also identified novel murine monoclonal antibodies specific to citrullinated fibrinogen that enhanced arthritis when coadministered with a submaximal dose of anti-CII antibodies and bound targets within the inflamed synovium of mice with CIA. These results demonstrate that antibodies against citrullinated proteins are centrally involved in the pathogenesis of autoimmune arthritis.     

Role of glycopeptide-specific T cells in collagen-induced arthritis: an example how post-translational modification of proteins may be involved in autoimmune disease.

Immunization of mice with type II collagen (CII), a cartilage-restricted protein, leads to collagen-induced arthritis (CIA), a model for rheumatoid arthritis (RA). CIA symptoms consist of an erosive joint inflammation caused by an autoimmune attack, mediated by both T and B lymphocytes. CD4+ alphabeta T cells play a central role in CIA, both by helping B cells to produce anti-CII antibodies, and by interacting with other cells in the joints, eg macrophages. In H-2q mice, most CII-specific CD4+ T cells recognize the CII(256-270) peptide presented on the major histocompatibility complex (MHC) class II Aq molecule. Post-translational modifications (hydroxylation and variable glycosylation) of the lysine residue at position 264 of CII generate at least four different T-cell determinants that are specifically recognized by distinct T-cell subsets. Most T cells recognize CII(256-270) glycosylated with the monosaccharide galactose, which is consequently immunodominant in CIA. Recent studies indicate that the arthritogenic T cells in CIA are glycopeptide-specific, suggesting that induction of self-tolerance may be rendered more difficult by glycosylation of CII. These data open the possibility that outoimmune disease may be caused by the creation of new epitopes by posttranslational modification of proteins under circumstances such as trauma, inflammation or ageing.     

雷公藤多甙对佐剂性关节炎模型大鼠踝关节相关指标的影响

背景:类风湿性关节炎是常见的自身免疫性疾病。近年来雷公藤多甙广泛应用于类风湿性关节炎治疗,其治疗过程中对关节滑膜炎症的影响及对类风湿性关节炎的预防作用有待研究。目的:观察雷公藤多甙对佐剂性关节炎模型大鼠踝关节相关指标的影响。设计:随机对照动物实验。单位:四川大学基础医学与法医学院组织胚胎学与神经生物学教研室。材料:选用20只健康清洁级雌性SD大鼠,体质量(200±15)g,鼠龄二三个月,由四川大学实验动物中心提供。氟氏完全佐剂为Sigma公司产品,雷公藤多甙为湖南株州制药三厂产品(批准文号:湘卫药准字(2005)第055172号。剂量:10mg/片)。方法:实验于2004-05/2006-03在四川大学组织胚胎学和神经生物学教研室完成。抽签法随机将大鼠分为正常组、模型组、预防组及治疗组,每组5只。正常组不造模,不给药物治疗;模型组于实验开始后,分别在各个大鼠左后足垫部皮下注射氟氏完全佐剂0.2mL,不给药物治疗;预防组造模方法同模型组,造模后第7天开始灌胃给予雷公藤多甙,用药剂量以大鼠体表面积换算公式计算,1次/d,每次30mg/kg,共7d;治疗组造模方法同模型组,造模后第19天开始灌胃给予雷公藤多甙,方式和疗程同预防组。①采用足跖容积法于造模前,造模后2,10,15,19,22,26d不同时间点观察记录大鼠原发侧与继发侧关节后肢肿胀程度。②根据其余未注射的3只肢体的病变程度及指间趾间关节是否发炎,评价大鼠关节炎指数(0分:肿胀度≤5%;1分:肿胀≤15%;2分:15%<肿胀≤30%;3分:30%<严重肿胀≤60%;4分:肿胀>60%),把每个关节的得分累计起来,即为每只大鼠的关节炎指数。③造模后28d取材,将大鼠灌注固定后,取完整踝关节切片,苏木精-伊红染色后观察大鼠踝关节滑膜组织的改变。主要观察指标:各组大鼠关节肿胀程度、关节炎指数及踝关节滑膜组织学观察。结果:大鼠20只均进入结果分析。①造模2d后,除正常组外,其他各组大鼠原发侧关节均出现明显肿胀,造模2～26d各时间点大鼠足跖容积均大于正常组(t=2.315～3.041,P<0.05);预防组大鼠造模后10,15,19,22,26d原发侧足跖容积小于模型组(t=2.064～2.683,P<0.05);治疗组大鼠造模后22,26d原发侧足跖容积小于模型组(t=2.112～2.578,P<0.05)。造模15d后,模型组和治疗组大鼠继发侧足跖容积均大于正常组(t=2.201～2.546,P<0.05),预防组大鼠造模15,19,22,26d继发侧足跖容积小于模型组(t=2.373～2.425,P<0.05);治疗组大鼠造模26d继发侧足跖容积小于模型组(P<0.05)。②造模14d,模型组大鼠关节炎指数为(8.3±2.0)分,预防组为(0.4±0.95)分,预防组较模型组明显降低(t=2.64,P<0.05);造模26天,治疗组为(7.3±1.3)分,明显低于模型组(11.2±0.9)分(t=3.26,P<0.05)。③正常组大鼠踝关节腔内干净,关节软骨表面光滑,软骨无退行性变,滑膜组织无增生。模型组大鼠原发侧踝关节滑膜增生,滑膜细胞数量增多,体积增大,排列为多层;滑膜下组织水肿,充血,炎性细胞浸润。模型组继发侧继发性病变表现为滑膜增生,踝关节滑膜下组织水肿。预防组原发侧踝关节滑膜与模型组比较,滑膜炎症反应减弱,增生程度减轻。继发侧踝关节滑膜未见明显增生。治疗组原发侧及继发侧踝关节滑膜与模型组比较,滑膜组织增生减少,炎症反应减轻。结论:雷公藤多甙能显著减轻大鼠足跖关节肿胀度,关节炎症指数,减轻踝关节滑膜病理改变,且能预防继发性病变的出现。     

Adenoviral delivery of soluble VEGF receptor 1 (sFlt-1) abrogates disease activity in murine collagen-induced arthritis

The angiogenic factor VEGF promotes synovitis and bone erosion in rheumatoid arthritis (RA). Previously, we have demonstrated that VEGF expression correlates with disease severity in RA patients and in murine collagen-induced arthritis (CIA). In this study, we adopted an adenoviral gene delivery system expressing soluble VEGF receptor 1 (sFlt-1) to further study the role of VEGF in CIA. Arthritis was induced in DBA/1 mice by injection of bovine collagen. Adenoviruses expressing human soluble VEGF receptor 1 (AdvsFlt-1), or without transgene (Adv0), were injected intravenously on the first day of arthritis. We found that disease severity and paw swelling were significantly suppressed in mice receiving AdvsFlt-1, when compared to untreated or Adv0-treated mice. Expression of sFlt-1 peaked 24 h after injection, with protein detectable in the liver, synovial issue and serum, but rapidly decreased by 72 h. The effect of sFlt-1 expression on signs of disease was paralleled by reduced joint destruction and decreased expression of the vascular marker von Willebrand factor. In summary, adenoviral delivery of human soluble VEGF receptor type 1 significantly suppressed disease activity in CIA. The actions of AdvsFlt-1 are likely to be mediated by reduced synovial neovascularization, and these results support the concept that VEGF blockade may be an effective therapeutic adjunct for the treatment of RA.     

CII-DC-AdTRAIL cell gene therapy inhibits infiltration of CII-reactive T cells and CII-induced arthritis

Previously, we described an APC-adenovirus (APC-Ad) FasL cell gene therapy method which could be used to deplete autoreactive T cells in vivo. FasL was toxic, however, and controlled regulation of FasL was not achieved. Here we describe an improved approach to delivering TNF-related apoptosis-inducing ligand (TRAIL) in vivo in which collagen II-induced (CII-induced) arthritis-susceptible (CIA-susceptible) DBA/1j mice were treated with CII-pulsed DCs that had been transfected with a novel Ad system. The Ad was engineered to exhibit inducible TRAIL under the control of the doxycycline-inducible (DOX-inducible) tetracycline response element (TRE). Four groups of mice were treated with CII-DC-AdTRAIL+DOX, CII-DC-AdTRAIL (no DOX), CII-DC-AdGFP+DOX, or DC-AdTRAIL+DOX (no CII), beginning 2 weeks after priming with CII in CFA. The incidence of arthritis and infiltration of T cells in the joint was significantly decreased in CII-DC-AdTRAIL+DOX-treated mice. The in vitro splenic T cell proliferative response and induction of IFN-gamma to bovine CII stimulation were also significantly reduced in mice treated with CII-DC-AdTRAIL+DOX. AdTRAIL+DOX was not toxic to DCs or mice but could induce activated T cells to undergo apoptosis in the spleen. Our results suggest that CII-DC-AdTRAIL+DOX cell gene therapy is a safe and effective method for inhibiting the development of CIA.     

血管活性肠肽对胶原诱导关节炎大鼠治疗的作用初探

目的探讨血管活性肠肽(VIP)对胶原诱导性关节炎(CIA)大鼠的免疫调节作用,为应用VIP治疗类风湿关节炎(RA)提供理论依据。方法采用尾根部皮内多点注射法注射天然Ⅱ型胶原(CⅡ),免疫雌性Wistar大鼠(60只),建立CIA模型。随机取CIA成模大鼠(5只/组)于初次免疫后14~35 d,腹腔内注射不同浓度的VIP。定期进行临床、实验室、影像学及病理指标评估。结果不同剂量VIP(0.1、1、5 nmol隔日1次,共2周)治疗后CIA大鼠,其临床、实验室、影像学及病理指标明显缓解;正常鼠于VIP给药5 nmol 2周后重要脏器功能、组织学未见明显异常。结论生理浓度的VIP体内可缓解CIA鼠关节局部及全身免疫炎性反应,5 nmol 2周以内的体内治疗量基本安全,提示VIP可作为治疗RA有潜力的制剂。     

Gene targeting by ribozyme against TNF-alpha mRNA inhibits autoimmune arthritis

Ribozymes are catalytic RNA that bind and cleave specific regions of target RNA. Therefore, protein synthesis by the target RNA may be specifically inhibited by ribozymes. In this study, we have investigated if ribozymes possess therapeutic activity on inflammatory processes in vivo, as judged from effects on an arthritis model. A hammerhead ribozyme against TNF-alpha was designed and its catalytic activity in vitro was verified. The ribozyme was employed in vivo without any delivery system, as the plasmid-based ribozyme was taken up adequately by various tissues in mice by intravenous injection. The ability of the ribozyme to regulate the development of collagen-induced arthritis (CIA), a model largely dependent on TNF-alpha, was investigated. Systemic administration of the ribozyme to mice immunized with collagen type II in CFA significantly reduced the development of CIA. No effect was observed with a catalytically inactive variant of the ribozyme. Furthermore, the ribozyme efficiently blocked cartilage and bone destruction in the joints and ameliorated established CIA. These data demonstrate for the first time that gene targeting by a ribozyme to inactivate TNF-alpha in vivo is highly efficient in suppressing autoimmune arthritis, thus providing proof of concept that it may be used as therapeutic tool for TNF-alpha-dependent chronic inflammatory disorders.     

Resistance to collagen-induced arthritis in a nonhuman primate species maps to the major histocompatibility complex class I region.

Type II collagen-induced arthritis (CIA) is an experimentally inducible autoimmune disorder that is, just like several forms of human arthritis, influenced by a genetic background. Immunization of young rhesus monkeys (Macaca mulatta) with type II collagen (CII) induced CIA in about 70% of the animals. One major histocompatibility complex (MHC) class I allele was present only in young animals resistant to CIA and absent in arthritic animals. This strong association suggests that the MHC class I allele itself, or a closely linked gene, determines resistance to CIA. The mechanism controlling the resistance to CIA becomes less efficient in aged animals since older rhesus monkeys, which were positive for the resistance marker, developed a mild form of arthritis. At the cellular level it is demonstrated that resistance to CIA is reflected by a low responsiveness of T cells to CII. This association between a specified MHC class I allele and resistance to an autoimmune disease points at the importance of the MHC class I region in the regulation of the immune response to an autoantigen.     

HLA-DQB1 polymorphism determines incidence, onset, and severity of collagen-induced arthritis in transgenic mice. Implications in human rheumatoid arthritis.

Certain HLA-DR alleles have been associated with predisposition to human rheumatoid arthritis (RA). There is also evidence that certain HLA-DQ alleles may also be important in determining susceptibility to RA. We have previously demonstrated that mice transgenic for HLA-DQ8, a DQ allele associated with susceptibility to RA, develop severe arthritis after type II collagen immunization. To investigate the influence of polymorphic difference at the DQ loci on susceptibility to arthritis, we generated mice transgenic for HLA-DQ6, an allele associated with a nonsusceptible haplotype. The DQ6 mice were found to be resistant to collagen-induced arthritis. We also assessed the combined effect of an RA-susceptible and an RA nonassociated DQ allele by producing double-transgenic mice expressing DQ6 and DQ8 molecules, representing the more prevalent condition found in humans where heterozygosity at the DQ allele is common. The double-transgenic mice developed moderate CIA when immunized with CII when compared with the severe arthritis observed in DQ8 transgenic mice, much like RA patients bearing both susceptible and nonsusceptible HLA haplotypes. These studies support a role for HLA-DQ polymorphism in human RA.     

Expression of a transgenic T cell receptor beta chain enhances collagen- induced arthritis

SWR/J transgenic (tg) mice were generated expressing the TCR beta chain derived from an anticollagen type II (CII) arthritogenic T cell clone. The SWR/J strain was selected because it is resistant to collagen-induced arthritis (CIA) and lacks the V beta gene segment used by the T cell clone. Expression of the tg beta chain on all thymocytes and peripheral lymph node T cells led to a more efficient anti-CII immune response, but did not confer CIA susceptibility to SWR/J mice. Nevertheless, this tg beta chain enhanced predisposition to CIA as (DBA/1 x SWR) F1 beta tg mice were more susceptible than normal F1 littermates. Our results demonstrate that the expression of the tg beta chain contributes to CIA susceptibility, but by itself it is not sufficient to overcome CIA resistance in the SWR/J strain.     

Adeno-associated virus-mediated delivery of IL-4 prevents collagen-induced arthritis

Immunomodulation of autoimmune inflammatory diseases like rheumatoid arthritis can be achieved by anti-inflammatory T2 cytokines such as interleukin (IL)-4 administered by gene therapy. In this study we investigated the efficiency of adeno-associated viruses (AAV) vectors in collagen-induced arthritis (CIA). After injection of AAV-LacZ in the tarsus area of mice, the expression of the transgene was localized in the deep muscles cells near the bone. LacZ expression was found in liver, heart and lung after i.m. injection of AAV-LacZ, showing a spread of the vector over the body. Anti-AAV neutralizing antibodies were detected in the serum after i.m. injection of AAV-LacZ, but they did not alter the transgene expression after re-administration of AAV-LacZ. Long-term IL-4 expression persisted 129 days after intra-muscular injection of 3.7 x 10(10) or 11.2 x 10(10) AAV-IL-4 p.p. (average 7.7 or 17.5 pg IL-4/mg proteins, respectively). More importantly, the treatment of CIA with AAV-IL-4 vector in mice produced a therapeutic benefit, since we show a diminished prevalence of the disease, a significant reduction in paw swelling, attenuated histological synovitis and a 10 days delayed onset of arthritis. This is the first evidence that AAV vector-mediated gene therapy using a T2 cytokine is efficient in an animal model of rheumatoid arthritis.     

Identification of an immunosuppressive epitope of type II collagen that confers protection against collagen-induced arthritis

We have previously reported that collagen-induced arthritis can be suppressed by intravenous injection of native type II (CII) but not type I collagen. We have now identified denatured fragments of CII capable of suppressing collagen-induced arthritis and inducing tolerance. Purified CII was cleaved with cyanogen bromide (CB), and the major resulting peptides were isolated. Female DBA/1 mice were administered OVA, native CII, or one of the CB peptides, intravenously, before immunization with native CII, 6 wk after immunization, mice tolerized with CII and CB11 had a markedly lower incidence of arthritis compared with controls. There was a correlation between the overall antibody response and the incidence of arthritis. In addition, animals tolerized with either CII or CB11 had a decreased antibody response not only to CII, but also to each of the other CB peptides tested. To identify the epitope involved in suppression of arthritis, five synthetic peptides, 21-26 amino acids in length, corresponding to selected regions of CB11, were generated. Each of the peptides was injected intravenously into mice before immunization. Only one of these, CB11 122-147, was capable of suppressing arthritis. In addition, mice given the synthetic peptide CB11 122-147 neonatally were suppressed for arthritis and antibody responsiveness when immunized with CII at 8 wk of age. Thus, we have identified CB11 122-147 as an epitope of CII important in induction of tolerance and suppression of disease. Further experiments narrowing down the pivotal amino acids for the immunogenicity of this epitope and the role this epitope plays in induction and regulation of disease will enhance our understanding of how the immune response to collagen affects autoimmune arthritis.