Role of T lymphocytes in murine collagen induced arthritis

Development of a 64Cu-labeled CD4+ T cell targeting PET tracer: evaluation of CD4 specificity and its potential use in collagen-induced arthritis

Background

CD4⁺ T cells are central inflammatory mediators in the pathogenesis of autoimmune rheumatoid arthritis (RA), as they are one of the dominating cell types in synovial inflammation. Molecular imaging of CD4⁺ T cells has potential role for early detection and monitoring of RA. Here, we developed a new radiotracer for in vivo immunoPET imaging of murine CD4⁺ T cells and tested it in the collagen-induced arthritis (CIA) mouse model of human RA.

Results

The tracer, [⁶⁴Cu]Cu-NOTA-CD4-F(ab)’2 ([⁶⁴Cu]Cu-NOTA-CD4), was generated from F(ab)’2 fragments of R-anti-mouse CD4 antibodies conjugated to the 2-S-(isothiocyanatbenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid (p-SCN-Bn-NOTA) chelator and radiolabeled with copper-64. Accumulation of the tracer and isotype control was evaluated in the CIA model and mice receiving whole-body irradiation (WBI) (5 Gy). The potential of [⁶⁴Cu]Cu-NOTA-CD4 for response assessment was evaluated in CIA induced mice treated with dexamethasone (DXM). Imaging data were compared with flow cytometry and immunohistochemistry (IHC) of inflammatory cells including CD4⁺ T cells. [⁶⁴Cu]Cu-NOTA-CD4 showed increased accumulation in T cell-rich tissues compared with isotype control (p < 0.0001). In addition, reduced accumulation of [⁶⁴Cu]Cu-NOTA-CD4 was observed in T cell-depleted tissue (p < 0.0001). Flow cytometry and IHC confirmed the increased infiltration of CD4⁺ T cells in CIA mice.

Conclusions

We developed and evaluated a new radiotracer, [⁶⁴Cu]Cu-NOTA-CD4, for immunoPET imaging of murine CD4⁺ T cells. [⁶⁴Cu]Cu-NOTA-CD4 was successfully synthesized by F(ab)’2 fragments of R-anti-mouse CD4 antibodies conjugated to a chelator and radiolabeled with copper-64. We found that our novel CD4 PET tracer can be used for noninvasive visualization of murine CD4⁺ T cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13550-022-00934-7.

Effect of a cathepsin K inhibitor on arthritis and bone mineral density in ovariectomized rats with collagen-induced arthritis

Objectives

Cathepsin K is expressed by osteoclasts and synovial fibroblasts and degrades key components of bone and cartilage. Inhibition of cathepsin K protease activity may be beneficial for the prevention of bone erosion and cartilage degradation in rheumatoid arthritis (RA). The collagen-induced arthritis (CIA) rat model is well established for studying the pathology and treatment of RA. We investigated the effect of ONO-KK1-300-01, a cathepsin K inhibitor (CKI), on arthritis and bone mineral density (BMD) in rats with CIA.

Methods

Seven-month-old female Sprague Dawley rats were divided into 5 groups: rats without CIA (CNT); CIA rats that underwent ovariectomy (OVX) and were treated with CKI; CIA rats that underwent OVX and were treated with vehicle (Veh); CIA rats that underwent sham surgery and were treated with CKI; and CIA rats that underwent sham surgery and were treated with Veh. CKI was orally administered at a dose of 15 mg/kg, thus initiating collagen sensitization, until death at 4 weeks. We evaluated hind paw thickness and the arthritis score every week until death. Radiographs of the resected left foot were obtained with a soft X-ray apparatus. Destruction of bone and cartilage was classified and scored as previously described by Engelhardt et al. BMD was measured by bone densitometry at the halfway point between the distal metaphysis and the diaphysis of the resected right femur. We also performed histomorphometry of the proximal left tibia, histological evaluation of arthritis, and a bone strength test.

Results

CKI administration significantly reduced hind paw thickness and the arthritis score, and prevented a decrease in BMD. The radiographic score was significantly lower in the CKI group than in the Veh group. In the histomorphometric analysis, bone-resorption parameters were significantly lower in the CKI groups than in the Veh groups. CKI significantly inhibited synovial proliferation in the CIA rats. In the bone strength test, the ultimate stress was significantly higher in the CKI groups than in the Veh groups.

Conclusion

Our findings indicate that cathepsin K inhibitors may inhibit systemic and local bone loss, ameliorate arthritis, and attenuate the decrease of bone strength in an animal model of arthritis.

Elevated expression of PD‑1 on T cells correlates with disease activity in rheumatoid arthritis

It is well known that lymphocytes are important in rheumatoid arthritis (RA). Programmed cell death-1 (PD‑1) is one of the immunosuppressive costimulatory molecules, which mediates an inhibitory effect. However, its role in RA remains to be fully elucidated. In the present study, the expression levels of PD‑1 on T cells in the peripheral blood (PB) and synovial fluid (SF) were determined using flow cytometry. In addition, the expression levels of PD‑1 on T cells in the PB and SF of patients with RA were further analyzed to determine correlation with markers of the autoimmune response, inflammation and disease activity in RA. Compared with healthy controls, the expression of PD‑1 on T cells in the PB was significantly elevated in patients with RA (P<0.0001). The expression of PD‑1 on T cells in the SF of patients with RA was significantly increased, compared with that in the autologous PB (P<0.0001). It was also found that the expression of PD‑1 on T cells in the PB of patients with RA was increased significantly in subjects with a high rheumatoid factor titer, high levels of inflammatory markers and a high disease activity score 28 (DAS28). The expression of PD‑1 on T cells in the SF of patients with RA was increased significantly in subjects with a high DAS28. These data showed that the expression of PD‑1 on T cells was elevated in patients with RA and was correlated with the disease activity.

Elevated Expression of Immunoreceptor Tyrosine-Based Inhibitory Motif (TIGIT) on T Lymphocytes is Correlated with Disease Activity in Rheumatoid Arthritis

Background

It is well known that lymphocytes play an important role in rheumatoid arthritis (RA). T cell immunoreceptors with immunoglobulin (Ig) and immunoreceptor tyrosine-based inhibitory motif (TIGIT) have immunosuppressive co-stimulatory molecules that mediate inhibitory effects, but their roles in RA are poorly understood.

Material/Methods

Were recruited 76 patients with RA and 33 healthy controls (HC). Clinical manifestations, laboratory measurements, physical examination, and medical history of RA patients were recorded. The expression of TIGIT on CD3⁺ T lymphocytes, B lymphocytes, monocytes, neutrophils, CD3⁺CD4⁺ T lymphocytes, and CD3⁺CD8⁺ T lymphocytes was determined using flow cytometry. The expression of TIGIT on T lymphocytes in patients with RA was further analyzed to investigate its correlations with markers of autoimmune response, inflammation, and disease activity in RA.

Results

Compared with HC, the expression levels of TIGIT on CD3⁺CD4⁺ T lymphocytes and CD3⁺CD8⁺ T lymphocytes were significantly increased in patients with RA (P < 0.01). The frequency of TIGIT-expressing CD3⁺CD4⁺ T lymphocytes was positively correlated with RF, increased ACPA, ESR, and CRP levels. The frequency of TIGIT-expressing CD3⁺CD8⁺ T lymphocytes was positively correlated with RF and ESR levels. Furthermore, the expression level of TIGIT on CD3⁺CD4⁺ T lymphocytes was positively correlated with the DAS28 score in RA.

Conclusions

The expression levels of TIGIT on T lymphocytes were elevated and correlated with disease activity in RA.

Mechanism of action of 5-arninosalicylic acid

5-Aminosalicylic Acid (5-ASA) has been used for over 50 years in the treatment of inflammatory bowel disease in the pro-drug form sulphasalazine (SASP). SASP is also used to treat rheumatoid arthritis. However whether the therapeutic properties of SASP are due to the intact molecule, the 5-ASA or sulphapyridine components is unknown. Several mechanisms of action have been proposed for 5-ASA and SASP including interference in the metabolism of arachidonic acid to prostaglandins and leukotrienes, scavenging,of reactive oxygen species, effects on leucocyte function and production of cytokines. However, it is unlikely that the anti-inflammatory properties of SASP and 5-ASA are due to several different properties but more likely that a single property of 5-ASA explains the theraapeutic effects of 5-ASA and SASP. Reactive oxygen species (ROS) are involved in the metabolism of prostaglandins and leukotrienes and can act as second messengers, and so the scavenging of ROS may be the single mechanism of action of 5-ASA that gives rise to its antiinflammatory effects in both inflammatory bowel disease and rheumatoid arthritis.

Establishment and characterization of a sustained delayed-type hypersensitivity model with arthritic manifestations in C57BL/6J mice

Introduction

Rheumatoid arthritis (RA) is a chronic progressive, inflammatory and destructive autoimmune disease, characterised by synovial joint inflammation and bone erosion. To better understand the pathophysiology and underlying immune mechanisms of RA various models of arthritis have been developed in different inbred strains of mice. Establishment of arthritis models with components of adaptive immunity in the C57BL/6J strain of mice has been difficult, and since most genetically modified mice are commonly bred on this background, there is a need to explore new ways of obtaining robust models of arthritis in this strain. This study was undertaken to establish and characterise a novel murine model of arthritis, the delayed-type hypersensitivity (DTH)-arthritis model, and evaluate whether disease can be treated with compounds currently used in the treatment of RA.

Methods

DTH-arthritis was induced by eliciting a classical DTH reaction in one paw with methylated bovine serum albumin (mBSA), with the modification that a cocktail of type II collagen monoclonal antibodies was administered between the immunisation and challenge steps. Involved cell subsets and inflammatory mediators were analysed, and tissue sections evaluated histopathologically. Disease was treated prophylactically and therapeutically with compounds used in the treatment of RA.

Results

We demonstrate that DTH-arthritis could be induced in C57BL/6 mice with paw swelling lasting for at least 28 days and that disease induction was dependent on CD4⁺ cells. We show that macrophages and neutrophils were heavily involved in the observed pathology and that a clear profile of inflammatory mediators associated with these cell subsets was induced locally. In addition, inflammatory markers were observed systemically. Furthermore, we demonstrate that disease could be both prevented and treated.

Conclusions

Our findings indicate that DTH-arthritis shares features with both collagen-induced arthritis (CIA) and human RA. DTH-arthritis is dependent on CD4⁺ cells for induction and can be successfully treated with TNFα-blocking biologics and dexamethasone. On the basis of our findings we believe that the DTH-arthritis model could hold potential in the preclinical screening of novel drugs targeting RA. The model is highly reproducible and has a high incidence rate with synchronised onset and progression, which strengthens its potential.

Effect of raloxifene on arthritis and bone mineral density in rats with collagen-induced arthritis

We studied the effect of raloxifene (RAL) on arthritis and bone mineral density (BMD) in rats with collagen-induced arthritis (CIA). Seven-month-old female Sprague-Dawley rats were divided into five groups: rats without CIA (CNT), CIA rats that underwent ovariectomy (OVX) and were treated with RAL (CIA + OVX + RAL), CIA rats that underwent OVX and were treated with vehicle (CIA + OVX + Veh), CIA rats that had sham surgery and were treated with RAL (CIA + sham + RAL), and CIA rats that had sham surgery and were treated with vehicle (CIA + sham + Veh). RAL was orally administered at 10 mg/kg every day for 3 weeks, beginning 1 week after initial sensitization until death at 4 weeks. Every week until death, we evaluated hind paw thickness and arthritis score. BMD was measured by peripheral quantitative computed tomography at the distal metaphysis and the diaphysis of the femur; we also performed histomorphometry of the proximal tibia and histological evaluation of arthritis. RAL administration suppressed hind paw thickness and arthritis score and prevented decreases in BMD and cortical thickness. In the histomorphometric analysis, bone-resorption parameters were significantly lower in the RAL groups than in the Veh groups. RAL significantly inhibited synovial proliferation in CIA rats. RAL effects on arthritis and bone were apparent regardless of whether an animal had undergone OVX. RAL could suppress arthritis and bone loss in estrogen-replete or -depleted rats. These findings, using an animal model, indicate the potential usefulness of RAL as an effective treatment for premenopausal RA patients as well as postmenopausal ones.

B cell depletion delays collagen-induced arthritis in mice: arthritis induction requires synergy between humoral and cell-mediated immunity

Rheumatoid arthritis is a systemic autoimmune disease. B cells are likely to play a critical role in arthritis pathogenesis, although it is unclear whether they are necessary for disease induction, autoantibody production, or disease progression. To assess the role of B cells in inflammatory arthritis, B cells were depleted using mouse anti-mouse CD20 mAbs in a mouse model of collagen-induced arthritis. CD20 mAbs effectively depleted mature B cells from adult DBA-1 mice. When B cells were depleted using CD20 mAbs before collagen immunization, there was a delay in disease onset and autoantibody production, with significantly diminished severity of arthritis both clinically and histologically. B cell depletion further delayed disease onset if initiated before, as well as after, collagen immunization. However, in both cases, the eventual reappearance of peripheral B cells triggered autoantibody production and the subsequent development of arthritis in collagen-sensitized mice. By contrast, B cell depletion after collagen immunizations did not have a significant effect on arthritis progression or severity. Thus, disease symptoms were only induced when peripheral B cells and their autoantibody products were present in collagen-immunized mice, documenting a critical role for B cells during the elicitation phase of collagen-induced arthritis. These studies suggest that B cell depletion strategies will be most effective when initiated early in the development of inflammatory arthritis, with sustained B cell depletion required to inhibit the production of isotype-switched pathogenic Abs and the evolution of joint inflammation and destruction.

Antigen-specific expansion of TCR Vbeta3+ CD4+ T cells in the early stage of collagen-induced arthritis and its arthritogenic role in DBA/1J mice

To investigate type II collagen (CII)-specific CD4+ T cell receptors involving in Collagen-induced arthritis (CIA) in DBA/1J mice as a model of rheumatoid arthritis in humans, TCR Vbeta usage in draining lymph nodes (dLNs) was assessed by flow cytometric analysis at 3, 5, and 8 weeks after bovine CII immunizations. In the early stage of CIA, the draining lymph node CD4+ T cells from CIA mice showed a higher proportion of CD4+ Vbeta3+ subsets compared with those from control mice. The CD4+ Vbeta3+ T cells were specifically and primarily expanded by antigen-specific stimulation in in vitro culture of dLNs lymphocytes and splenocytes from CIA mice. In addition, CII-reactive response was observed when CD4+ Vbeta3+ T cells were added to a non-responding T cell population. The adoptive transfer of CD4+ Vbeta3+ T cells produced exaggerated arthritis compared with that in the control group. Our results indicate that CD4+ Vbeta3+ T cells, which were selectively expanded in dLN of CIA mice, play a pivotal role in CIA pathogenesis.

Tracking of Proinflammatory Collagen-Specific T Cells in Early and Late Collagen-Induced Arthritis in Humanized Mice

Rheumatoid arthritis is a chronic inflammatory disease associated with certain HLA-DR4 subtypes. The target autoantigen(s) is unknown, but type II collagen (CII) is a candidate, with a single immunodominant DR4-restricted 261-273 T cell epitope (CII(261-273)). In the present study, we have prepared HLA-DR4:CII(261-273) tetramers and analyzed peripheral blood, lymph node, and synovial fluid cells from DR4-transgenic mice with early and late collagen-induced arthritis to draw a fuller picture of the role of CII-reactive Th cells in disease development. Their frequencies increased approximately 20-fold in blood 1-2 wk postimmunization, and even more in acutely arthritic joints. Our data strongly suggest that CII-specific Th cells are necessary, but not sufficient for collagen-induced arthritis. The CII-specific Th cells displayed an activated proinflammatory Th1 phenotype, and their expansion correlated with onset and severity of arthritis and also with anti-CII Ab levels. Surprisingly, shortly after the first clinical signs of arthritis, activated HLA-DR4:CII tetramer(+) cells became undetectable in the synovial fluid and rare in the blood, but persisted in lymph nodes. Consequently, future human studies should focus on patients with early arthritis, and on their synovial cells, to re-evaluate the occurrence and pathogenic importance of CII-specific or other Th cells in rheumatoid arthritis.

TACI-ligand interactions are required for T cell activation and collagen-induced arthritis in mice

Interactions of the tumor necrosis factor superfamily members B lymphocyte stimulator (BLyS) and a proliferation-inducing ligand (APRIL) with their receptors-transmembrane activator and CAML interactor (TACI) and B cell maturation molecule (BCMA)-on B cells play an important role in the humoral immune response. Whereas BCMA is restricted to B cells, TACI is also expressed on activated T cells; we show here that TACI-Fc blocks the activation of T cells in vitro and inhibits antigen-specific T cell activation and priming in vivo. In a mouse model for rheumatoid arthritis (RA), an autoimmune disease that involves both B and T cell components, TACI-Fc treatment substantially inhibited inflammation, bone and cartilage destruction and disease development. Thus, BLyS and/or APRIL are important not only for B cell function but for T cell-mediated immune responses. Inhibition of these ligands might have therapeutic benefits for autoimmune diseases, such as RA, that involve both B and T cells.

H2-Mbeta 1 and H2-Mbeta 2 heterodimers equally promote clip removal in I-A(q) molecules from autoimmune-prone DBA/1 mice

Antigen-presenting cells degrade endocytosed antigens, e.g. collagen type II, into peptides that are bound and presented to arthritogenic CD4(+) helper T cells by major histocompatibility complex (MHC) class II molecules. Efficient loading of many MHC class II alleles with peptides requires the assistance of H2-M (HLA-DM in humans), a heterodimeric MHC class II-like molecule that facilitates CLIP removal from MHC class II molecules and aids to shape the peptide repertoire presented by MHC class II to CD4(+) T cells. In contrast to the HLA-DM region in humans, the beta-chain locus is duplicated in mice, with the H2-Mb1 beta-chain distal to H2-Mb2 and the H2-Ma alpha-chain gene. H2-M alleles appear to be associated with the development of autoimmune diseases. Recent data showed that Mbeta1 and Mbeta2 isoforms are differentially expressed in isolated macrophages and B cells, respectively. The tissue expression and functional role of these heterodimers in promoting CLIP removal and peptide selection have not been addressed. We utilized the human T2 cell line, which lacks part of chromosome 6 encompassing the MHC class II and DM genes, to construct transgenic cell lines expressing the MHC class II heterodimer I-A(q) alone or in the presence of H2-Malphabeta1 or H2-Malphabeta2 heterodimers. Both H2-M isoforms facilitate the exchange of CLIP for cognate peptides on I-A(q) molecules from arthritis-susceptible DBA/1 mice and induce a conformational change in I-A(q) molecules. Moreover, I-A(q) cell-surface expression is not absolutely dependent on H2-M molecules. These data suggest that I-A(q) exhibits a high affinity for CLIP since virtually all I-A(q) molecules on T2 cells were found to be associated with CLIP in the absence of both H2-M isoforms.

High frequencies of identical T cell clonotypes in synovial tissues of rheumatoid arthritis patients suggest the occurrence of common antigen-driven immune responses

OBJECTIVE

To investigate T cell antigen receptor (TCR) clonotypes in rheumatoid arthritis (RA) lesions.

METHODS

Reverse transcriptase-polymerase chain reaction with TCR V beta family-specific primers and subsequent single-strand conformation polymorphism (SSCP) analysis were performed. Direct nucleotide sequencing was also conducted.

RESULTS

A distinct clonal expansion of T cells was observed in the synovium. Furthermore, identical bands in samples of different areas of the same lesion were obtained by SSCP analysis. Nucleotide sequencing revealed that T cell clonotypes of identical mobility on SSCP analysis had the same nucleotide sequence and thus were identical clones. In 6 RA patients, 60-100% of the expanded T cell clonotypes had identical migration patterns in 2 different samples, indicating that this percentage represents commonly existing T cell clonotypes in the affected joint. Furthermore, the J beta 2.1 gene segment was used predominantly by the TCR V beta clonotypes that commonly expanded in the different portions of the same joint.

CONCLUSION

These results suggest that the immune response in RA is not random, but rather is driven by common stimuli.

Borrelia burgdorferi-specific T lymphocytes induce severe destructive Lyme arthritis

This is the first documentation that Borrelia burgdorferi-specific T lymphocytes are involved in the pathogenesis of Lyme arthritis. We present direct evidence that T lymphocytes obtained from inbred LSH hamsters vaccinated with a whole-cell preparation of Formalin-inactivated B. burgdorferi sensu stricto isolate C-1-11 in adjuvant conferred on naive recipient hamsters the ability to develop severe destructive arthritis when challenged with B. burgdorferi sensu stricto isolates C-1-11 and 297. By contrast, recipients infused with normal T lymphocytes and challenged with B. burgdorferi sensu stricto isolates C-1-11 and 297 failed to develop severe destructive arthritis. The T lymphocytes transferred were obtained from the lymph nodes of vaccinated and nonvaccinated hamsters by depleting B lymphocytes by using monoclonal antibody 14-4-4s (< 1% B lymphocytes by flow cytometric analysis). The enriched T lymphocytes showed enhanced proliferation to stimulation with concanavalin A and failed to respond to lipopolysaccharide. Moreover, only the enriched T lymphocytes from vaccinated hamsters proliferated on exposure to a whole-cell preparation of B. burgdorferi sensu stricto isolate C-1-11 in the presence of mitomycin-treated syngeneic antigen-presenting cells. These results demonstrate that B. burgdorferi-specific T lymphocytes primed by vaccination with a whole-cell preparation of inactivated B. burgdorferi sensu stricto isolate C-1-11 in adjuvant are involved in the development of severe destructive arthritis. Additional experiments are needed to define the precise mechanism(s) responsible for the development of Lyme arthritis.

Restricted expression of T cell receptor V beta and lymphokine genes in arthritic joints of a TCR V beta a (H-2q) mouse strain-BUB/BnJ-with collagen-induced arthritis

Type II collagen-induced arthritis (CIA) is an animal model of inflammatory polyarthritis with clinical and pathological features resembling rheumatoid arthritis (RA). We compared the expression of T cell receptor (TCR) V beta genes in T cells isolated from the inflamed joints, draining lymph nodes and the spleens of BUB/BnJ (H-2q) mice (BUB) during the early phase of CIA. We also investigated the profiles of cytokine gene expression in T cells obtained from the same tissues. We found that the expression of TCR V beta s, in arthritic joints of mice, during the early phase of the disease was limited to TCR V beta 3 and 10 gene families. In contrast, TCR V beta 4, 7, and 15 were predominant in the draining lymph nodes (LNs) and TCR V beta 2, 6, and 14 were predominant in the spleens of arthritic mice. Molecular cloning and sequence analysis revealed that the T cell populations in the arthritic joints were oligoclonal as determined by the limited N-D-N region diversity observed in the sequenced clones. These results demonstrate, for the first time, that (1) joint infiltrating T cells in TCR V beta a genotype mice use a restricted repertoire of TCR V beta genes; (2) there was oligoclonal expansion of infiltrating T cells in arthritic joints in mice with collagen-induced arthritis. Our results on cytokine gene expression in the arthritic joints of BUB mice indicate that Th-1-like T cell derived cytokines may be the predominant cytokines in the arthritic joints as illustrated by the presence of transcripts for IL-2 and IFN-gamma but not IL-4. In summary, our results provide evidence that T cells with restricted specificities, and more specificially, Th-1 type T cells, are crucial in the early phase of collagen induced arthritis in mice.

An ear swelling reaction for in vivo monitoring of inflammatory T cell activity in collagen-arthritic rats

T cells play a dominant role in the pathogenesis of collagen-induced arthritis (CIA). The effector mechanism involves a delayed-type hypersensitivity reaction in the synovial joint. Here we describe a new test system, named a flare reaction, to monitor directly this inflammatory T cell function. It is shown that type II collagen (CII) injected into the pinna of the ear is a target for CII-reactive inflammatory T cells formed during the early pathogenesis of CIA. The inflammatory swelling of the joint and the CII-injected ear in CIA rats develop in a coordinated manner. This assay greatly facilitates monitoring of in vivo activated inflammatory T cells during the induction of CIA.

T cell regulation of collagen-induced arthritis in mice. III. Is T cell vaccination a valuable therapy?

Since T cells play a critical role in collagen-induced arthritis (CIA), CD4+ T cell hybridomas were derived from DBA/1 mice immunized with bovine type II collagen (CII). The hybrid clones selected were Thy-1-2+, CD4+, CD8-, T cell receptor (TcR) alpha beta + and produced interleukin-2 in response to CII peptides presented by I-Aq molecules. The clones were collagen type-specific and recognized CII from many species except the mouse. More precisely, the reactivity was directed against the immunodominant cyanogen bromide-cleaved fragment CB11(II). Analysis of the TcR carried by the T cell hybridomas showed that they used identical V alpha and J alpha (V alpha BMB, J alpha 20) gene segments and two distinct V beta (V beta 1 and V beta 4) associated with the J beta 2.5 gene segment. Interestingly, the junctional regions were highly conserved in structure and length. These findings may indicate a strong in vivo selection by the antigen for a particular combination of both alpha and beta chains of the TcR. Inoculation of irradiated anti-CII T cell hybrids into DBA/1 mice, before priming with CII, altered the course of the disease resulting in either a long-lasting suppression or an exacerbation of CIA whereas a control CD4+ hybridoma with an unrelated specificity did not influence the development of arthritis. However, the regulatory effect of anti-CII T cell clones was unpredictable, suggesting that the TcR structure may not solely account for the modulation of CIA and that T cell vaccination is not a reliable method for inducing suppression of CIA.

Exacerbation of established collagen-induced arthritis in mice treated with an anti-T cell receptor antibody

OBJECTIVE

To investigate the effect of T cell depletion on established collagen-induced arthritis (CIA) in mice, using monoclonal antibodies (MAb) to T cell receptor alpha/beta (TCR alpha/beta). In addition, experiments using anti-CD3 MAb were performed for comparison.

METHODS

CIA was induced in male DBA/1 mice by immunizing them twice with bovine type II collagen (CII). The arthritis score and anti-CII antibody titers were examined serially. Proportions of T cells were determined by fluorescence-activated cell sorter (FACS) analysis on spleen cells or peripheral blood cells.

RESULTS

When anti-TCR alpha/beta MAb was injected on the day of CII priming, no arthritis was detected in association with depressed anti-CII antibody titers. Unexpectedly, however, when MAb was given after arthritis was established, a rapid exacerbation of arthritis was observed, which resulted in ankylosis of most joints. Anti-CII antibody titers were not affected. The addition of anti-TCR gamma/delta MAb had no effect on the augmented arthritis. T cell depletion by anti-CD3 MAb during established CIA also caused an enhancement of arthritis, which was, however, weak and only transient. FACS analysis revealed that the early improvement of arthritis after the transient augmentation seen in the mice treated with anti-CD3 MAb paralleled the early recovery of alpha/beta T cells in the periphery.

CONCLUSION

The present results support the concept that alpha/beta T cells, in general, may play a regulatory role in the clinical course of murine CIA after disease onset. Therefore, caution is recommended when using intensive T cell-targeted therapy in patients with rheumatoid arthritis.

2-Buten-4-olide (2-B4O) inhibits type II collagen-induced arthritis in Lewis rats

2-Buten-4-olide (2-B4O) is an endogenous substance which suppresses appetite and/or food intake. We studied its effect on type II collagen-induced arthritis (CIA) in Lewis rats, an animal model for human rheumatoid arthritis. Bovine type II collagen with incomplete Freund's adjuvant was injected intradermally into Lewis rats to induce CIA. 2-B4O (50 or 100 mg/kg) significantly inhibited the expression of the clinical symptoms when administered i.p. daily from day 1 to 21 after immunization. Furthermore, administration of 2-B4O daily from day 15 to 21 significantly reduced the severity of symptoms in established CIA. In addition, the progression of soft tissue swelling and articular bone erosions were suppressed by daily administration of 2-B4O. 2-B4O also significantly suppressed the delayed-type hypersensitivity (DTH) response to type II collagen at doses of 50 and 100 mg/kg. Finally 2-B4O significantly inhibited the formation of anti-type II collagen antibody at a dose of 100 mg/kg, but not at 50 mg/kg. These results suggest that 2-B4O has the strong inhibitory effects and therapeutic usefulness effects on CIA through the suppression of immune responses to type II collagen.

Prevention of collagen-induced arthritis with an antibody to gp39, the ligand for CD40

The ligand for the CD40 antigen is a 39-kilodalton protein, gp39, expressed on the surface of activated CD4+ T cells and is essential for thymus-dependent humoral immunity. The role of gp39-CD40 interactions in autoimmune disease was investigated in vivo with the use of an antibody that blocks their interactions (anti-gp39). Arthritis induced in mice by immunization with type II collagen was inhibited by anti-gp39. Anti-gp39 blocked the development of joint inflammation, serum antibody titers to collagen, the infiltration of inflammatory cells into the subsynovial tissue, and the erosion of cartilage and bone. Thus, interference with gp39-CD40 interactions may have therapeutic potential in the treatment of autoimmune disease.

Autoimmune recognition of cartilage collagens

Recent advances in basic research on the immune system and molecular biology of cartilage components have greatly increased our understanding of the role of autoimmunity in inflammatory diseases affecting joints, particularly rheumatoid arthritis. Many of these diseases are common and their complex pathogenesis probably involves a large number of genes polymorphic in the population as well as environmental factors. Characteristic features of inflammatory arthritis include expansion of the synovial tissue into a pannus containing lymphocytes and macrophages, autoimmune reactions against cartilage antigens, and erosion of cartilage. Since hyaline cartilage of the articular surfaces is the only structure within the joint known to contain joint-specific antigens this tissue is the prime suspect as the target of the autoimmune This review will first present the capacity of the immune system to discriminate between self and non-self structures, and then summarize our current understanding of the structures of cartilage collagens. Subsequently we will discuss how the immune system normally interacts with cartilage and how such interactions can lead to arthritis. We propose that collagen-induced arthritis (CIA) is valuable for understanding the autoimmune recognition of cartilage collagen which precedes the outbreak of arthritis and may perpetuate its chronicity, and serves as an animal model of rheumatoid arthritis.

T cell repertoire and autoimmune diseases

Self-reactivity and autoimmunity are processes related to the breakage of self-tolerance that can be distinguished by their different clinical outcome and are widely accepted cornerstones of immunology. The finding that several potentially autoaggressive cells contribute to the repertoire of healthy individuals has stimulated a great deal of experimental work aimed at understanding the mechanisms that prevent autoimmune pathology. In this review we will consider the basic principles, and our present knowledge of the rules that preside over the interplay of the immune system with self-components. One viewpoint stresses the importance of major histocompatibility complex (MHC) and non-MHC genes in determining genetic predisposition to develop autoimmune phenomena. At a different level there is a strong interest in understanding the mechanisms of processing and presentation of self antigens, especially during ontogeny. Another topic of major interest concerns the interaction between MHC genes and the T cell receptor (TcR) complex as well as the identification of TcR V genes that are preferentially expressed by autoimmune T cells. All of these aspects are evaluated in the context of tolerance based on deletion and anergy. Finally we will propose a general model of autoimmunity based on the most recent findings concerning the biological activity of exogenous superantigens.

Cell-mediated transfer of collagen-induced arthritis in mice and its application to the analysis of the inhibitory effects of interferon-gamma and cyclophosphamide

We developed a convenient and reliable procedure for the cell-mediated passive transfer of type II collagen (CII)-induced arthritis (CA). Spleen cells from DBA/1 mice with CA were intravenously transferred into syngeneic recipient mice. Arthritis developed only in those recipients which had received whole-body x-irradiation (8 Gy) just before cell transfer and intraperitoneally given soluble CII without adjuvant immediately after transfer. Non-immunized splenocytes could not induce arthritis even in irradiated recipients given soluble CII. Development of arthritis depended on the number of cells transferred; 5 x 10(7) cells induced severe and long-lasting arthritis in every recipient approximately 10 days after transfer. Severity of this arthritis was clinically and histologically similar to classical CA in donors. Arthritogenic splenocytes were generated in donors no later than 20 days after priming with CII in Freund's complete adjuvant, when arthritis had yet to occur, and were detected for more than 5 weeks. One splenocyte population responsible for transferring arthritis was CD4+ T cells. We then applied this system to show that prophylactic treatment of CII-immunized mice with cyclophosphamide (CY, 7 mg/kg), but not interferon-gamma (IFN-gamma, 10(5) U/mouse), suppressed the arthritogenic ability of their spleen cells, although both treatments inhibited the development of CA. Treatment of recipients with IFN-gamma, however, inhibited the development of arthritis upon transfer with CII-immunized splenocytes. These results indicate that CY and IFN-gamma act at the induction and effector phases of arthritogenic lymphocytes, respectively. Thus, this system facilitates investigation of pathological mechanisms of CA, and of mechanisms of anti-arthritics.

Characterization of the T cell receptor repertoire causing collagen arthritis in mice

Collagen type II-induced arthritis (CIA) is generated in susceptible rodent strains by intradermal injections of homologous or heterologous native type II collagen in complete Freund's adjuvant. Symptoms of CIA are analogous to those of the human autoimmune disease, rheumatoid arthritis. CIA is a model system for T cell-mediated autoimmune disease. To study the T cell receptor (TCR) repertoire of bovine type II-specific T cells that may be involved in the pathogenesis of CIA in DBA/1Lac.J (H-2q) mice, 13 clonally distinct T cell hybridomas specific for bovine type II collagen have been established and the alpha and beta chains of their TCRs have been analyzed. These T cell hybridomas recognize epitopes that are shared by type II collagens from distinct species and not by type I collagens, and exhibit a highly restricted TCR-alpha/beta repertoire. The alpha chains of the TCRs employ three V alpha gene subfamilies (V alpha 11, V alpha 8, and V alpha 22) and four J alpha gene segments (J alpha 42, J alpha 24, J alpha 37, and J alpha 32). The V alpha 22 is a newly identified subfamily consisting of approximately four to six members, and exhibits a high degree of polymorphism among four mouse strains of distinct V alpha haplotypes. In addition, the beta chains of the TCRs employ three V beta gene subfamilies (V beta 8, V beta 1, and V beta 6), however the V beta 8.2 gene segment is preferentially utilized (58.3%). In contrast, the J beta gene segment usage is more heterogeneous. On the basis of the highly limited TCR-alpha/beta repertoire of the TCRs of the panel of bovine type II-specific T cell hybrid clones, a significant reduction (60%) of the incidence of arthritis in DBA/1Lac.J mice is accomplished by the use of anti-V beta 8.2 antibody therapy.

Anti-tumor necrosis factor ameliorates joint disease in murine collagen-induced arthritis

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.

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.

Identification of an immunodominant type-II collagen peptide recognized by T cells in H-2q mice: self tolerance at the level of determinant selection

The T cell recognition of type-II collagen (CII) in H-2q mice, susceptible to CII-induced arthritis, was analyzed. With the use of T cell hybridomas derived from rat CII-immunized mice, a peptide corresponding to amino acids 245-270 on chick CII was found to harbor a T cell epitope which is present on heterologous CII (chick, rat, human, and bovine CII) but not on autologous CII. It was shown that this epitope was located within amino acids 260-270, although flanking regions in either direction were necessary for proper recognition. A peptide corresponding to human CII (256-270) was used for further studies. A single amino acid difference at position 266 between mouse CII (aspartic acid) and heterologous CII (glutamic acid) strongly influenced recognition of this peptide. No response towards the mouse peptide was seen with any of the T cell hybridomas. Inhibition studies revealed that the mouse peptide did not bind as well to major histocompatibility complex as the corresponding heterologous peptide. Both peptides gave rise to a T cell response after immunization. However, immunization with the heterologous peptide resulted in a response strictly directed to rat CII and the immunogen while immunization with the autologous peptide elicited T cells which reacted in a heteroclitic fashion, with a stronger response to the heterologous peptide than to the autologous peptide, and did respond to rat CII but not to mouse CII. We suggest that aspartic acid in position 266 results in a cryptic determinant in mouse CII which is neither recognized after CII immunization nor capable of tolerance induction. A glutamic acid at position 266, however, gives rise to an immunodominant epitope which is recognized by a large proportion of the T cells activated after immunization with heterologous CII.

Low-affinity antibodies against collagen type II produced by lymph node cells are associated with pathology in collagen-induced arthritis in rats

The relationship between the affinity of antibodies against type II collagen (CII) and arthritis was studied in rats immunized intradermally with bovine CII. Disease was associated with a higher mean titre of serum antibody and a lower mean functional antibody affinity (determined in a chaotropic dissociation assay) against both the immunizing bovine CII and homologous autoantigenic rat CII in comparison with the response in immunized rats that did not develop disease. The functional affinity of the antibodies present in the serum was found to correlate with that of antibodies produced in culture by cells from the lymph nodes draining the site of immunization with collagen. The reduction in mean functional affinity in the anti-collagen response may be the result of the increased production of antibodies of the lowest affinity and a consequent broadening of the affinity heterogeneity. It is proposed that production of low-affinity antibodies in the lymph nodes draining the site of immunization with collagen is important in the pathogenesis of collagen-induced arthritis in rats.

Restricted heterogeneity in T-cell antigen receptor V beta gene usage in the lymph nodes and arthritic joints of mice

We have used PCR to study the expression of T-cell antigen receptor beta RNA containing particular variable region (V) elements from transcripts directly in the cells isolated from joints and lymph nodes of B10.Q mice (H-2q) immunized with chicken type II collagen. Our data show that the T cells present in arthritic joints expressed only a few V beta transcripts--V beta 2, -6, -7, -8.2, -9, -10, and -15. V beta 6 and -8.2 were expressed predominantly (six out of seven animals) while others were expressed at a relatively low level in different animals. In lymph node cells, transcripts for V beta 6, -8.2, and -9 were detected in four out of seven animals. The data indicate that in collagen-induced arthritis there is a restrictive usage of TCR V beta elements and that V beta 6 and -8.2 are probably used preferentially.

Interleukin-1 enhances the development of type II collagen-induced arthritis only in susceptible and not in resistant mice

The development of type II collagen-induced arthritis (CIA) in DBA/1 mice is readily accelerated by treatments with interleukin-1 beta (IL-1 beta). In an attempt to further characterize this IL-1 beta-mediated enhancement of CIA, we first examined the effects of IL-1 beta treatments in other "CIA-susceptible" strains and "CIA-resistant" mice. It was observed that treatments with IL-1 beta also enhanced the onset of arthritis in two B10 recombinant CIA-susceptible strains, B10.T (6R) and B10.DA, and in the SJL mice which develop CIA with a relatively low and variable incidence. On the other hand, IL-1 beta failed to augment the expression of arthritic disease in several CIA-resistant strains. We also investigated the potentiating effects of IL-1 beta in mice that were depleted of L3T4+ T cells. It was found that the ability of IL-1 beta to accelerate the development of CIA was significantly reduced in DBA/1 mice pretreated with the monoclonal anti-L3T4 antibody. In further studies, we demonstrated that the induction of CIA upon transfer with collagen-primed spleen cells was also augmented by IL-1 beta, and this enhancing effect by IL-1 beta on the adoptive transfer of CIA was associated with a significant increase in the levels of serum anti-collagen antibodies. Moreover, IL-1 beta treatments did not potentiate the induction of CIA in mice that were transferred with either collagen-immune splenic cells that were depleted of L3T4+ T cells or only T cells obtained from collagen-immunized animals. However, IL-1 beta enhanced the development of arthritis in animals that had been transferred with two subpopulations of collagen-immune cells: (i) enriched T cells and (ii) splenic cells that were depleted of L3T4+ T cells. Thus, IL-1 beta potentiated the inflammatory responses in animals that were genetically predisposed to developing arthritis. In contrast, IL-1 beta was incapable of accelerating the development of arthritis in various mouse strains that were genetically resistant to CIA. The administration of IL-1 beta also failed to potentiate the development of CIA in L3T4-deficient mice or in animals transferred with collagen-primed spleen cells that were depleted of L3T4+ T cells. These results indicate that IL-1 beta readily accelerates the induction of arthritis when the disease is present, but that IL-1 beta is incapable of promoting the expression of the arthritis in the absence of underlying disease.

Monoclonal antibodies and arthritis

Monoclonal antibodies to certain cell surface constituents on lymphocytes, monocytes and macrophages have been administered to Lewis rats with developing, established or adoptively transferred arthritis, to determine any immunomodulatory properties. Anti-CD4 antibodies against helper T-lymphocytes produced a dose related inhibition of developing arthritis; high dose levels completely suppressed all symptoms of arthritis and these rats were resistant to further attempts to induce arthritis. Anti-Ia (MHCII) antibodies also inhibited arthritis in a dose related manner; anti-pan T antibodies delayed the onset of arthritis, but antibodies against CD8 and IL-2 receptor positive cells were without effect. Development of type II collagen-induced arthritis was also inhibited by anti-CD4 treatment. Established arthritis could be temporarily inhibited by anti-CD4 antibodies, but rebound of arthritis invariably occurred after stopping treatment, as is the case with cyclosporin A. Similar results with anti-CD4 antibodies were obtained during treatment of arthritis adoptively transferred by arthritogenic T-lymphocytes. From these experiments it is clear that CD4 positive T-lymphocytes have a major role in the induction of adjuvant arthritis and that interaction between CD4 and Ia bearing cells is important. The rebound of arthritis that occurred after withdrawal of anti-CD4 treatment during established disease infers that cells in addition to helper T-lymphocytes are involved in the chronicity of arthritis, but these remain to be elucidated. These findings are discussed in relation to results with monoclonal antibodies in other models of arthritis and human rheumatoid arthritis; the prospects for human therapy are also discussed.

Collagen induced arthritis as an experimental model for rheumatoid arthritis. Immunogenetics, pathogenesis and autoimmunity

The type II collagen (CII) induced arthritis animal model (CIA) provides opportunities to study the nature of autoimmune reactions leading to arthritis and may be used as a model for rheumatoid arthritis (RA). Thus, in similarity with RA, the CIA model, when induced with autologous CII, shows a chronic and progressive disease course. The susceptibility to both RA and CIA are correlated to the expression of certain MHC class II allotype genes. In both diseases are autoantibodies to CII and rheumatoid factors produced. Immunohistopathology of affected joints show in both diseases a dominance of activated macrophages/fibroblasts with a significant infiltration of activated T cells and an infiltration of granulocytes. We do here suggest that both RA and CIA are dependent on a synergy between delayed type hypersensitivity and immune complex mediated inflammatory mechanisms and that CIA provides opportunities for studies of immunospecific reactions leading to arthritis.

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.

Treatment with gamma-interferon triggers the onset of collagen arthritis in mice

We investigated the effect of gamma-interferon (gamma-IFN) on the development of type II collagen (CII)-induced arthritis. DBA/1 mice were immunized with rat CII and 16 days later, were treated with subcutaneous injections of recombinant rat gamma-IFN into the right paws twice a week. Compared with controls, the gamma-IFN-treated mice developed arthritis with a higher frequency and severity. Immunohistochemical analysis of gamma-IFN-treated paws from CII-immunized mice revealed an increase in the numbers of class II antigen-expressing cells and an infiltration of CD4+ lymphocyte-like cells. The auto-antibody response toward CII was suppressed by gamma-IFN treatment. The findings implicate gamma-IFN in a role that triggers arthritis by enhancing local inflammatory processes in the joints, or possibly, by permitting homing of T cells to the joints.

The enhancing effect of cyclosporine A and sulfasalazine on the prevention of rejection in rat cardiac allografts

Sulfasalazine (SASP) has been used for many years as a disease-modifying agent in inflammatory bowel disease and in rheumatoid arthritis. However, its mode of action is not entirely clear. Evidence has been accumulated which indicates that its efficacy is due to an immunomodulatory effect. In the present communication, we report that SASP has an immunomodulatory capacity in an experimental rat cardiac allograft model. A combination of 100 mg/kg per day of SASP given orally until rejection and 10 mg/kg per day of cyclosporine A (CyA) given orally for 10 days resulted in a significantly increased graft survival time as compared to that in animals given CyA alone.

Immunoregulation in arthritis. A review on synovial immune reactions in RA and in some experimental animal models for arthritis

Local synovial immune reactions have during recent years been characterized both in human arthritides, particularly in rheumatoid arthritis (RA), and in animal models for arthritis. Common characteristics of human RA on one hand and experimental adjuvant arthritis and collagen arthritis on the other hand, are induced expression of class II transplantation antigens on synovial cells close to the cartilage and presence of activated T lymphocytes in close proximity to these class II expressing cells. The present review aims to describe some implications of these and subsequent findings both concerning the analysis of the pathogenesis of RA and concerning some therapeutic implications derived from parallel studies on relevant features of the human RA and the respective animal models for arthritis.