Enhanced production of interleukin-6 in mice with type II collagen–induced arthritis

We established an interleukin-6 (IL-6)–dependent cell line from murine plasmacytoma MOPC-104E cells. This cell line (designated PIL-6) was found to respond to murine and to human IL-6, but not to any other cytokines. We used this cell line to investigate the involvement of IL-6 production in type II collagen–induced arthritis in DBA/1 mice. Only marginal IL-6 activity was detected in sera from DBA/1 mice inoculated with Freund's complete adjuvant (FCA) alone, with an unrelated protein (bovine serum albumin) plus FCA, or with type II collagen plus Freund's incomplete adjuvant. However, enhanced IL-6 activity was observed in DBA/1 mice that had been injected with type II collagen plus FCA to induce arthritis. The elevated level of serum IL-6 activity was associated with high levels of IL-6 produced when lymph node cells from arthritic mice were stimulated in vitro with type II collagen. We also found that the L3T4+ T cell subset is responsible for the enhanced production of IL-6 in arthritic mice. The results are discussed in the context of potential roles of IL-6 in the induction and/or expression of chronic, progressive arthritis.     

The influence of silicone implantation on type II collagen-induced arthritis in mice

Objective. To determine whether silicone implantation exacerbates autoimmune disease in a murine experimental model of arthritis. Methods. DBA/1 mice were implanted with silicone in the form of an elastomer, gel, or oil, and immunized with type II collagen. The influence of silicone implantation on collagen-induced arthritis and the immune response to type II collagen were determined by comparison against control mice receiving sham implantation. Adjuvant effects of silicone implantation were examined by measuring cytokine levels in implanted animals and assessing autoantibodies against proteins extracted from recovered silicone implants. Results. No adverse influence of silicone implantation on the clinical aspects of collagen-induced arthritis was observed. Further, polydimethylsiloxane silicone oil failed to serve as an adjuvant in the immune or arthritogenic response to type II collagen in mice. Cytokine analysis indicated that tumor necrosis factor α levels were lower and interleukin-2 levels were higher in silicone-implanted mice. The development of arthritis increased protein binding to implanted elastomers and gel, and autoantibodies against silicone-bound proteins were present in sera from arthritic mice and absent in sera from nonarthritic mice. Conclusion. The data suggest that silicone implantation may result in autoantibodies against silicone-bound proteins, and the presence of arthritis may either provoke or increase the level of such autoantibodies. However, silicone implantation did not increase the incidence or severity of disease compared with sham-operated controls. Thus, it appears that autoantibodies against silicone-bound proteins may not have pathologic significance in this experimental model of arthritis.     

Characterization of the antibody response in mice with type II collagen-induced arthritis, using monoclonal anti-type II collagen antibodies

Twenty monoclonal antibodies reactive with type II collagen were characterized as to their determinant specificity and their reactivity with cartilage-derived components. The monoclonal antibodies reacted with 7 different epitopes on the native type II collagen triple helical structure. Antibodies defining 3 of these epitopes occurred more frequently in sera from arthritic mice than in sera from nonarthritic mice. In vivo injection of some selected autoreactive antibodies caused synovitis, but in no case did it give rise to full-blown arthritis.     

Plasma and bone osteocalcin levels in rats with type II collagen-induced arthritis

Osteocalcin levels in plasma and bone were measured by enzyme immunoassay in rats with arthritis induced by immunization with type II collagen and in untreated control rats. Compared with levels in control rats, the plasma levels of osteocalcin in arthritic rats were markedly decreased 1-3 weeks after immunization; during weeks 8-14, these levels were significantly increased. The osteocalcin content of tarsal bones changed in parallel with the plasma levels. These data suggest that osteocalcin levels in the plasma of arthritic rats reflect alterations in bone formation activity.     

CD44 expression on chondrocytes in knees of DBA/1 mice with type II collagen-induced arthritis.

OBJECTIVE: To investigate aspects of CD44 expression in the cartilage destruction of the knees of mice with collagen-induced arthritis. METHODS: DBA/1 mice were immunized with bovine type II collagen emulsified with Freund's incomplete adjuvant. Histological changes in the knees were evaluated in sections stained with hematoxylin and eosin, toluidine blue, and immunostaining using anti-CD44 monoclonal antibodies. RESULTS: CD44 expression was observed in the synovial lining and articular chondrocytes. A total of 10/10 knees had CD44-positive synovial lining cells at 6 weeks after immunization, which was higher than that at 4 weeks (7 of 10 knees, p < 0.05). At 4 weeks 3 of 10 knees with CD44-positive chondrocytes were observed, and 7 of 10 knees at 6 weeks after immunization. The number of knees at 6 weeks was higher than that at 4 weeks (p < 0.01). Nine of 10 knees showed loss of metachromasia on toluidine blue staining at 6 weeks after immunization, which was higher than the number at 4 weeks. The grade of metachromasia loss and the length of time after immunization were significantly correlated (p < 0.05, Spearman rank correlation; p = 0.46). CONCLUSION: These findings suggest that CD44 may play some role in the early stage of cartilage destruction in DBA/1 mice immunized with type II collagen.     

Suppression of type II collagen-induced arthritis by monoclonal antibodies.

Some mouse monoclonal antibodies raised against chicken type II collagen suppressed or delayed the onset of chicken type II collagen-induced arthritis in DBA/1 mice. This was correlated with the suppression of anti-mouse type II collagen antibody responses following immunization with chicken type II collagen. The epitopes recognized by the suppressive antibodies were found to be present on cyanogen bromide (CB)-digested collagen peptides CB-11 and CB-12. This was also confirmed by the finding that administration of the CB-11 or CB-12 peptide suppressed the induction of arthritis.     

Suppression of type II collagen-induced arthritis by intragastric administration of soluble type II collagen.

Although oral administration of protein antigens may lead to specific immunologic unresponsiveness, this method of immunoregulation has not been applied to models of autoimmune disease. Type II collagen-induced arthritis is an animal model of polyarthritis induced in susceptible mice and rats by immunization with type II collagen, a major component of cartilage. Intragastric administration of soluble type II collagen, prior to immunization with type II collagen in adjuvant, suppresses the incidence of collagen-induced arthritis. Administration of denatured type II collagen has no observable effect on the incidence or severity of the disease. The overall magnitude of the antibody response is not significantly reduced in collagen-fed mice as compared to controls. While the isotype distribution of the anti-collagen antibodies is similar in the two groups, there is a tendency toward reduced IgG2 responses in the collagen-fed mice.     

C57BL/6小鼠胶原诱导关节炎的特异性细胞及体液免疫反应

目的观察并比较C57BL/6小鼠初次和加强免疫Ⅱ型胶原后的特异性细胞及体液免疫应答,探讨特异性免疫应答在胶原诱导关节炎发病中的意义。方法用鸡Ⅱ型胶原(CⅡ)在C57BL/6小鼠尾部皮内注射,诱导胶原性关节炎(CIA)。分别取初次免疫后19d及加强免疫后7、28dCIA小鼠脾脏淋巴细胞,CⅡ体外刺激扩增后,采用5-溴脱氧尿嘧啶(BrdU)掺入法和流式细胞术分别测定其扩增情况和表型;并通过流式细胞术测定外周血中细胞内细胞因子干扰素(IFN)-γ、白细胞介素(IL)-4的水平分析Th1和Th2亚群的变化;同时用酶联免疫吸附试验(ELISA)测定不同时期CIA模型血清中抗CⅡ抗体的表达。结果①免疫后不同时间,CIA模型组外周血中CD4+IFN-γ+细胞百分率明显高于对照组(P<0.01),但CIA模型组内不同时间CD4+IFN-γ+细胞百分率差异无统计学意义;②特异性增生实验显示,CIA模型组CD4+T细胞中BrdU+细胞率均高于对照组,但加强免疫后BrdU+细胞率明显低于初次免疫(72±6)%,并且有逐渐降低的趋势;初次免疫后CD4+IFN-γ+细胞百分率为(13±4)%,加强免疫后阳性细胞百分率也下降;③ELISA法测定不同时间血清中CIA模型组抗CⅡ抗体水平,28d吸光度(A)值达到最高,其后逐渐减低,到35d左右(即加强免疫后14d)出现较低的抗体水平。结论C57BL/6小鼠加强免疫反应中特异     

Identification of new quantitative trait loci in mice with collagen-induced arthritis

OBJECTIVE: Collagen-induced arthritis (CIA) in the mouse is one of the most widely used autoimmune experimental models, with many features similar to rheumatoid arthritis. This study sought to identify potential genetic regulatory mechanisms of CIA in major histocompatibility complex-matched (H2-q) F(2) hybrid mice. METHODS: We used 126 polymorphic markers to perform simple sequence-length polymorphism analysis on 290 F(2) hybrids of arthritis-susceptible (DBA/1J) and arthritis-resistant (FVB/N) inbred mouse strains. The major clinical traits (disease severity and onset) were assessed, and serum antibodies specific to type II collagen (CII) were determined by enzyme-linked immunosorbent assay in 270 F(2) mice. Lymph nodes from 94 F(2) mice were used to test the ratio of CD4 to CD8 by fluorescence-activated cell sorter analysis, and cell proliferation was determined by XTT test. RESULTS: Two quantitative trait loci (QTLs) identified in previous studies were confirmed; these were severity-controlling Cia2 and onset-controlling Cia4 on chromosome 2. Moreover, we identified 5 new QTLs, 1 for CII-specific IgG2a antibodies on chromosome 5, 2 controlling the CII-specific IgG1 antibody response on chromosomes 10 and 13, 1 for the CD4:CD8 ratio on chromosome 2, and 1 for cell proliferation (measured by XTT test) on chromosome 16. Complement component C5 was identified as the probable main candidate gene for the QTLs Cia2 and Cia4. F(2) mice carrying a 2-basepair deletion of C5, the FVB/N allele, had low incidence and less severe disease as compared with those carrying the DBA/1J allele. CONCLUSION: This genome scan provides additional evidence confirming the role of C5 as a probable candidate gene for Cia2 and Cia4 loci, and identifies new QTLs controlling new traits in autoimmune arthritis.     

Membrane complement regulators protect against the development of type II collagen-induced arthritis in rats

OBJECTIVE: To investigate changes in the distribution patterns of membrane complement regulators (MCRs) during the development of type II collagen-induced arthritis (CIA) and to examine the protective effects of these molecules against the augmentation of CIA in the knee joint. METHODS: Immunohistochemistry was used to examine the distribution of the MCRs Crry, DAF, and CD59 in the synovium of knee joints before and 2, 4, and 10 weeks after induction of CIA by immunization with type II collagen. In addition, at 2 or 10 weeks after induction of CIA, rats were injected intraarticularly with anti-Crry and/or anti-CD59 as the F(ab')2 fraction of monoclonal antibodies (mAb). Knee joint swelling and histologic changes in the synovium were examined 2 weeks after mAb injection. RESULTS: Synovial expression of Crry, DAF, and CD59 decreased in parallel with increased inflammation. When Crry and CD59 were functionally blocked at 2 weeks after the induction of CIA, swelling of the knee joints was markedly increased. Blocking of either regulator alone had no effect on swelling. Thickening of the synovial surface and proliferation of subsynovial tissue were all increased after blocking Crry and CD59, whereas blocking of either MCR alone had no effect. When both Crry and CD59 were blocked, deposits of membrane attack complex were found in the synovium. CONCLUSION: Our findings indicate that in rats with CIA and severely inflamed synovium, local expression of MCR is reduced. The MCRs Crry and CD59 appear to suppress the development of CIA.     

Suppressive oligonucleotides protect against collagen-induced arthritis in mice

OBJECTIVE: To examine whether systemic administration of oligonucleotides (ODNs), known to inhibit the production of proinflammatory cytokines, alters host susceptibility to collagen-induced arthritis (CIA), a murine model of rheumatoid arthritis (RA). METHODS: CIA was induced by injecting DBA/1 mice with type II collagen (CII) in Freund's complete adjuvant, followed 3 weeks later by CII in Freund's incomplete adjuvant. The effect of suppressive ODNs on the incidence and severity of disease was monitored, as were immune correlates of CIA. RESULTS: Suppressive ODNs administered during the inductive phase of CIA significantly reduced the incidence and severity of arthritis. Treatment with suppressive ODNs significantly decreased serum titers of pathogenic IgG anti-CII autoantibodies and interferon-gamma production by collagen-reactive T cells. CONCLUSION: Suppressive ODNs may be of therapeutic value in the treatment of RA, and potentially other autoimmune diseases.     

Plasmid encoding interleukin-4 in the amelioration of murine collagen-induced arthritis

OBJECTIVE: To evaluate the therapeutic effect of the administration of plasmid encoding interleukin-4 (IL-4) via gene-gun delivery and via intradermal injection on collagen-induced arthritis (CIA). METHODS: IL-4 plasmid was administered by gene-gun delivery and intradermal injection to DBA/1 mice immunized with type II collagen (CII). The therapeutic effect on the development of CIA was evaluated clinically with a visual scoring method for arthritis and serologically by enzyme-linked immunosorbent assays and polymerase chain reaction. RESULTS: Treatment with IL-4-expressing plasmid significantly reduced the incidence and severity of CIA, including a reduction in the anti-CII antibody level. In particular, gene-gun delivery had a higher immunosuppressive effect on CIA compared with intradermal injection. As shown by in vitro stimulation assay, the spleen cells from mice immunized with CII and treated with IL-4 plasmid via gene gun exhibited higher Th2 cytokine responses compared with cells treated with control plasmid after in vitro stimulation with CII. CONCLUSION: The results of this study suggest that treatment with IL-4 plasmid may constitute a new clinical use of cytokine gene therapy for rheumatoid arthritis.