David D. Brand

Collagen-induced arthritis

The collagen-induced arthritis (CIA) mouse model is the most commonly studied autoimmune model of rheumatoid arthritis. Autoimmune arthritis is induced in this model by immunization with an emulsion of complete Freunds adjuvant and type II collagen (CII). This protocol describes the steps necessary for acquisition, handling and preparation of CII, as well as selection of mouse strains, proper immunization technique and evaluation of the arthritis incidence and severity. Typically, the first signs of arthritis appear in this model 21–28 days after immunization, and identification of the arthritic limbs is not difficult. Using the protocol described, the investigator should be able to reproducibly induce a high incidence of CIA in various strains of genetically susceptible mice as well as learn how to critically evaluate the pathology of the disease. The total time for the preparation of reagents and the immunization of ten mice is about 1.5 h.

IL-17–dependent cellular immunity to collagen type V predisposes to obliterative bronchiolitis in human lung transplants

Bronchiolitis obliterans syndrome (BOS), a process of fibro-obliterative occlusion of the small airways in the transplanted lung, is the most common cause of lung transplant failure. We tested the role of cell-mediated immunity to collagen type V [col(V)] in this process. PBMC responses to col(II) and col(V) were monitored prospectively over a 7-year period. PBMCs from lung transplant recipients, but not from healthy controls or col(IV)-reactive Goodpastures syndrome patients after renal transplant, were frequently col(V) reactive. Col(V)-specific responses were dependent on both CD4+ T cells and monocytes and required both IL-17 and the monokines TNF-alpha and IL-1beta. Strong col(V)-specific responses were associated with substantially increased incidence and severity of BOS. Incidences of acute rejection, HLA-DR mismatched transplants, and induction of HLA-specific antibodies in the transplant recipient were not as strongly associated with a risk of BOS. These data suggest that while alloimmunity initiates lung transplant rejection, de novo autoimmunity mediated by col(V)-specific Th17 cells and monocyte/macrophage accessory cells ultimately causes progressive airway obliteration.

Immunopathogenesis of collagen arthritis.

Abstract. Collagen-induced arthritis (CIA) is an animal model of autoimmunity that has been studied extensively because of its similarities to rheumatoid arthritis (RA). CIA is induced in genetically susceptible strains of mice by immunization with type II collagen (CII), and both T cell and B cell immunity to CII are required for disease manifestation. Like RA, CIA is primarily an autoimmune disease of articular joints and susceptibility to CIA is linked to specific class II molecules of the major histocompatibility complex (H-2r and H-2q). Recently, it was demonstrated that transgenic expression of HLA-DR1 (*0101) or DR4 (*0401) molecules associated with susceptibility to RA also conferred susceptibility to CIA in the mouse model. The T cell response to CII has been extensively characterized in both the DR transgenic and naturally susceptible mouse strains, including the antigenic determinants recognized, the role of post transcriptional modifications of these determinants in the pathogenic T cell response, and the cytokines produced. Like most class II-mediated autoimmune diseases, the cytokine production of CII-specific T cells reflects a Th1 phenotype of the autoimmune response. While the direct role of T cells in the pathogenesis of CIA is unclear, the B cell response in terms of anti-CII immunoglobulin is critical to the development of the disease. This response, predominated by the IgG2 isotype, requires the activation of the complement cascade for the development of CIA. In recent years, the pathogenesis of this model has been studied extensively and the CIA model is proving to be a valuable asset for the design of new immunotherapeutics for the potential treatment of RA and other autoimmune diseases.

Cutting Edge: All-Trans Retinoic Acid Sustains the Stability and Function of Natural Regulatory T Cells in an Inflammatory Milieu

Recent studies have demonstrated that plasticity of naturally occurring CD4+Foxp3+ regulatory T cells (nTregs) may account for their inability to control chronic inflammation in established autoimmune diseases. All-trans retinoic acid (atRA), the active derivative of vitamin A, has been demonstrated to promote Foxp3+ Treg differentiation and suppress Th17 development. In this study, we report a vital role of atRA in sustaining the stability and functionality of nTregs in the presence of IL-6. We found that nTregs treated with atRA were resistant to Th17 and other Th cell conversion and maintained Foxp3 expression and suppressive activity in the presence of IL-6 in vitro. atRA decreased IL-6R expression and signaling by nTregs. Of interest, adoptive transfer of nTregs even from arthritic mice treated with atRA suppressed progression of established collagen-induced arthritis. We suggest that nTregs treated with atRA may represent a novel treatment strategy to control established chronic immune-mediated inflammatory diseases.

Anti-Type V Collagen Lymphocytes that Express IL-17 and IL-23 Induce Rejection Pathology in Fresh and Well-Healed Lung Transplants

Immunity to collagen V [col(V)] contributes to lung ‘rejection.’ We hypothesized that ischemia reperfusion injury (IRI) associated with lung transplantation unmasks antigenic col(V) such that fresh and well‐healed lung grafts have differential susceptibility to anti‐col(V)‐mediated injury; and expression of the autoimmune cytokines, IL‐17 and IL‐23, are associated with this process. Adoptive transfer of col(V)‐reactive lymphocytes to WKY rats induced grade 2 rejection in fresh isografts, but induced worse pathology (grade 3) when transferred to isograft recipients 30 days post‐transplantation. Immunhistochemistry detected col(V) in fresh and well‐healed isografts but not native lungs. Hen egg lysozyme‐reactive lymphocytes (HEL, control) did not induce lung disease in any group. Col(V), but not HEL, immunization induced transcripts for IL‐17 and IL‐23 (p19) in the cells utilized for adoptive transfer. Transcripts for IL‐17 were upregulated in fresh, but not well‐healed isografts after transfer of col(V)‐reactive cells. These data show that IRI predisposes to anti‐col(V)‐mediated pathology; col(V)‐reactive lymphocytes express IL‐17 and IL‐23; and anti‐col(V)‐mediated lung disease is associated with local expression of IL‐17. Finally, because of similar histologic patterns, the pathology of clinical rejection may reflect the activity of autoimmunity to col(V) and/or alloimmunity.

Cleavage of denatured natural collagen type II by neutrophil gelatinase B reveals enzyme specificity, post-translational modifications in the substrate, and the formation of remnant epitopes in rheumatoid arthritis

During acute inflammation, leukocytes release proteolytic enzymes including matrix metalloproteinases (MMPs), but the physiopathological mechanisms and consequences of this process are not yet fully understood. Neutrophils, the predominant leukocyte type, produce neutrophil collagenase (MMP‐8) and gelatinase B (MMP‐9) but not the tissue inhibitors of MMPs. After stimulation, these cells also activate MMPs chemically. In arthritic diseases, neutrophils undergo great chemoattraction to the synovium, are activated by interleukin‐8, and are stimulated to release gelatinase B in vivo. Production levels and net activities of gelatinase B were found to be absent in degenerative osteoarthritis but significantly increased in rheumatoid arthritis. The cleavage sites in cartilage type II collagen by gelatinase B were determined by a combination of reverse phase high‐performance liquid chromatography, Edman degradation, and mass spectrometry analysis. The analysis revealed the site specificity of proline and lysine hydroxylations and O‐linked glycosylation, the cleavage specificities by gelatinase B, and the preferential absence and presence of post‐translational modifications at P2′ and P5′, respectively. Furthermore, gelatinase B leaves the immunodominant peptides intact, which are known from studies with (autoreactive) T cells. Lysine hydroxylation was detected at a critical position for T‐cell activation. These data lend support to the thesis that extracellular proteolysis and other post‐translational modifications of antigenic peptides may be critical in the establishment and perpetuation of autoimmune processes.—Van den Steen, P.E., Proost, P., Grillet, B., Brand, D.D., Kang, A.H., Van Damme, J., Opdenakker, G. Cleavage of denatured natural collagen type II by neutrophil gelatinase B reveals enzyme specificity, post‐translational modifications in the substrate, and the formation of remnant epitopes in rheumatoid arthritis. FASEB J. 16, 379–389 (2002)

Role of SMAD and Non-SMAD Signals in the Development of Th17 and Regulatory T Cells

Whereas TGF-β is essential for the development of peripherally induced Foxp3+ regulatory T cells (iTreg cells) and Th17 cells, the intracellular signaling mechanism by which TGF-β regulates development of both cell subsets is less understood. In this study, we report that neither Smad2 nor Smad3 gene deficiency abrogates TGF-β–dependent iTreg induction by a deacetylase inhibitor trichostatin A in vivo, although the loss of the Smad2 or Smad3 gene partially reduces iTreg induction in vitro. Similarly, SMAD2 and SMAD3 have a redundant role in development of Th17 in vitro and in experimental autoimmune encephalomyelitis. In addition, ERK and/or JNK pathways were shown to be involved in regulating iTreg cells, whereas the p38 pathway predominately modulated Th17 and experimental autoimmune encephalomyelitis induction. Therefore, selective targeting of these intracellular TGF-β signaling pathways during iTreg and Th17 cell development might lead to the development of therapies in treating autoimmune and other chronic inflammatory diseases.

Adoptive Transfer of Human Gingiva‐Derived Mesenchymal Stem Cells Ameliorates Collagen‐Induced Arthritis via Suppression of Th1 and Th17 Cells and Enhancement of Regulatory T Cell Differentiation

OBJECTIVE Current approaches offer no cures for rheumatoid arthritis (RA). Accumulating evidence has revealed that manipulation of bone marrow-derived mesenchymal stem cells (BM-MSCs) may have the potential to control or even prevent RA, but BM-MSC-based therapy faces many challenges, such as limited cell availability and reduced clinical feasibility. This study in mice with established collagen-induced arthritis (CIA) was undertaken to determine whether substitution of human gingiva-derived mesenchymal stem cells (G-MSCs) would significantly improve the therapeutic effects. METHODS CIA was induced in DBA/1J mice by immunization with type II collagen and Freunds complete adjuvant. G-MSCs were injected intravenously into the mice on day 14 after immunization. In some experiments, intraperitoneal injection of PC61 (anti-CD25 antibody) was used to deplete Treg cells in arthritic mice. RESULTS Infusion of G-MSCs in DBA/1J mice with CIA significantly reduced the severity of arthritis, decreased the histopathology scores, and down-regulated the production of inflammatory cytokines (interferon-γ and interleukin-17A). Infusion of G-MSCs also resulted in increased levels of CD4+CD39+FoxP3+ cells in arthritic mice. These increases were noted early after infusion in the spleens and lymph nodes, and later after infusion in the synovial fluid. The FoxP3+ Treg cells that were increased in frequency mainly consisted of Helios-negative cells. When Treg cells were depleted, infusion of G-MSCs partially interfered with the progression of CIA. Pretreatment of G-MSCs with a CD39 or CD73 inhibitor significantly reversed the protective effect of G-MSCs on CIA. CONCLUSION The role of G-MSCs in controlling the development and severity of CIA mostly depends on CD39/CD73 signals and partially depends on the induction of CD4+CD39+FoxP3+ Treg cells. G-MSCs provide a promising approach for the treatment of autoimmune diseases.

Collagen-induced arthritis.

The mouse model collagen‐induced arthritis (CIA) is a widely studied autoimmune model of rheumatoid arthritis. In this model, autoimmune arthritis is induced by immunization with type II collagen (CII) emulsified in complete Freunds adjuvant. This unit describes the steps necessary for the acquisition, handling, and preparation of CII, in addition to the selection of mouse strains, proper immunization technique, and methods for evaluation of the incidence and severity of arthritis. In this model, the first signs of arthritis appear approximately 21 to 28 days after immunization. The protocols in this unit should provide the investigator with all the necessary information required to reproducibly induce a high incidence of CIA in genetically susceptible strains of mice, and to critically evaluate the pathology of the disease. Curr. Protoc. Immunol. 89:15.5.1‐15.5.25.

Th-17, Monokines, Collagen Type V, and Primary Graft Dysfunction in Lung Transplantation

RATIONALE The pathogenesis of primary graft dysfunction (PGD), a serious complication of lung transplantation, is poorly understood. Human studies and rodent models have shown that collagen type V (col[V]), stimulates IL-17-dependent cellular immunity after lung transplantation. OBJECTIVES To determine whether patients with end-stage lung disease develop pretransplant col(V)-specific cellular immunity, and if so, the impact of this response on PGD. METHODS Trans-vivo delayed-type hypersensitivity (TV-DTH) assays were used to evaluate memory T-cell responses to col(V) in 55 patients awaiting lung transplantation. Pa(O(2))/Fi(O(2)) index data were used to assess PGD. Univariate risk factor analysis was performed to identify variables associated with PGD. Rats immunized with col(V) or irrelevant antigen underwent lung isografting to determine if prior anti-col(V) immunity triggers PGD in the absence of alloreactivity. MEASUREMENTS AND MAIN RESULTS We found that 58.8% (10/17) of patients with idiopathic pulmonary fibrosis, and 15.8% (6/38) of patients without idiopathic pulmonary fibrosis tested while on the wait list for a lung transplant were col(V) DTH positive. Col(V) reactivity was CD4(+) T-cell and monocyte mediated, and dependent on IL-17, IL-1beta, and tumor necrosis factor (TNF)-alpha. Pa(O(2))/Fi(O(2)) indices were impaired significantly 6-72 hours after transplantation in col(V)-reactive versus nonreactive patients. Univariate risk factor analysis identified only preoperative TV-DTH to col(V) and ischemic time as predictors of PGD. Finally, in a rat lung isograft model, col(V) sensitization resulted in significantly lower Pa(O(2))/Fi(O(2)), increased local TNF-alpha and IL-1beta production, and a moderate-to-severe bronchiolitis/vasculitis when compared with control isografts. CONCLUSIONS The data suggest that activation of innate immunity by col(V)-specific Th-17 memory cells represents a novel pathway to PGD after lung transplantation.