Inhibition of macropinocytosis blocks antigen presentation of type II collagen in vitro and in vivoin HLA-DR1 transgenic mice
© von Delwig et al.; licensee BioMed Central Ltd. 2006
Received: 16 February 2006
Accepted: 24 April 2006
Published: 16 May 2006
Professional antigen-presenting cells, such as dendritic cells, macrophages and B cells have been implicated in the pathogenesis of rheumatoid arthritis, constituting a possible target for antigen-specific immunotherapy. We addressed the possibility of blocking antigen presentation of the type II collagen (CII)-derived immunodominant arthritogenic epitope CII259–273 to specific CD4 T cells by inhibition of antigen uptake in HLA-DR1-transgenic mice in vitro and in vivo. Electron microscopy, confocal microscopy, subcellular fractionation and antigen presentation assays were used to establish the mechanisms of uptake, intracellular localization and antigen presentation of CII by dendritic cells and macrophages. We show that CII accumulated in membrane fractions of intermediate density corresponding to late endosomes. Treatment of dendritic cells and macrophages with cytochalasin D or amiloride prevented the intracellular appearance of CII and blocked antigen presentation of CII259–273 to HLA-DR1-restricted T cell hybridomas. The data suggest that CII was taken up by dendritic cells and macrophages predominantly via macropinocytosis. Administration of amiloride in vivo prevented activation of CII-specific polyclonal T cells in the draining popliteal lymph nodes. This study suggests that selective targeting of CII internalization in professional antigen-presenting cells prevents activation of autoimmune T cells, constituting a novel therapeutic strategy for the immunotherapy of rheumatoid arthritis.
Professional antigen-presenting cells (APCs), such as dendritic cells (DCs), macrophages and B lymphocytes, play a pivotal role in the pathogenesis of autoimmune diseases in animal models by presenting arthritogenic T cell epitopes to autoimmune T cells [1–3] Adoptive transfer of ex vivo cultured autoantigen-specific DCs has been shown to induce a variety of experimental autoimmune diseases, such as autoimmune diabetes, experimental autoimmune encephalomyelitis and erosive inflammatory arthritis [4–6]. DCs in situ are often surrounded by a cluster of T cells  and are thought to internalize autoantigens from the extracellular matrix and cartilage for intracellular processing and presentation of arthritogenic epitopes to specific CD4 T cells, as well as to induce activation of B lymphocytes in patients with rheumatoid arthritis (RA) . B lymphocytes have also been shown to be critical both as antigen-presenting and antibody-secreting cells in the pathogenesis of autoimmune arthritis [3, 9–11] High efficiency of antigen presentation of arthritogenic epitopes by macrophages has also been demonstrated [12, 13].
Type II collagen (CII, α1(II)3), the most abundant fibrillar protein of articular cartilage , is considered an important autoantigen involved in the pathogenesis of collagen-induced arthritis in mice and RA in humans [15, 16] In addition, collagen has been shown to deliver a direct maturation stimulus to DCs , possibly via ligation of Toll-like receptor 4 (TLR4) or by binding to cell surface integrins [18, 19], suggesting that DCs can present collagen T cell epitopes without additional inflammatory or danger signals. A direct co-stimulatory activity of collagen has, however, not been demonstrated in vivo as there is no evidence that collagen by itself displays adjuvant activity . No information is available on the mechanisms engaged in CII uptake into professional APCs for presentation of arthritogenic epitopes to CD4 T cells.
Several mechanisms have been described to mediate internalization of antigens into APCs, including phagocytosis, macropinocytosis, receptor-mediated endocytosis and caveolar endocytosis. Phagocytosis follows the recognition of particles ≥0.25 μm by specific receptors and an F-actin microfilament-dependent internalization into phagosomes . Macropinocytosis does not require ligation of specific receptors and is accompanied by membrane ruffling and F-actin-dependent uptake into large macropinosomes of 0.15 to 5.0 μm . Receptor-mediated endocytosis of smaller particles and molecules engages clathrin-coated pits and F-actin recruitment at endocytic sites , while clathrin-independent endocytosis is dependent on intact caveolae and lipid rafts . In contrast to other internalization mechanisms, caveolar endocytosis does not deliver antigens to lysosomes and, therefore, does not appear to play a major role in antigen processing and presentation [2, 25].
In this report, we show that CII was taken up preferentially via macropinocytosis into DCs and macrophages from HLA-DR1 transgenic mice for antigen presentation of both the glycosylated and non-glycosylated forms of the arthritogenic CII259–273 epitope to CD4 T cells. Treatment of mice with an inhibitor of macropinocytosis also prevented activation of CII259–273-specific T cells in vivo.
Materials and methods
Human CII purified from normal human cartilage was purchased from MD BioSciences (Zürich, Switzerland). The glycosylated peptide (GIAGF KGEQGPKGET; K = GalHyL264) corresponding to epitope CII259–273 GalHyL264 was synthesized using β-D-galactopyranosyl-5-hydroxy-L-lysine, as described previously . The non-glycosylated peptide pCII259–273 was purchased from GenScript Corp. (Piscataway, NJ, USA), and purity was confirmed by high-performance liquid chromatography.
In all experiments described in this study we used previously reported mice transgenic for HLA-DR1 on a major histocompatibility complex (MHC) class II-deficient background (designated C57BL/6J0-0 HLA-DR1), which carried full-length genomic constructs for HLA-DRA1*0101 and HLA-DRB1*0101, developed by one of us (DMA) . Experiments described in this report have been performed under the terms of Animals (Scientific Procedures) Act 1986, and authorized by the Home Secretary, Home Office UK. The work has been approved by the Ethical Review Committee of the University of Newcastle upon Tyne.
Culture media ingredients and inhibitors were purchased from Sigma Chemical Co. (Dorset, UK), unless stated otherwise. Cells were grown in culture medium (RPMI 1640 medium containing 3 mM L-glutamine, 50 μM 2-mercaptoethanol, 10% FBS and 30 μg/ml gentamycin). T cell hybridomas HCII-9.1 (specific for the non-glycosylated peptide) and HCII-9.2 (specific for the glycosylated peptide) have been described previously . Macrophages were grown from femoral bone marrow cells in culture medium supplemented with 5% horse serum, 1 mM sodium pyruvate, 10 mM HEPES and 7.5% of a supernatant from the L929 cell line as a source of macrophage colony stimulating factor (M-CSF), as described . Macrophages were activated with 10 U/ml recombinant IFN-γ (R&D Systems, Abingdon, UK) for 24 hours (purity approximately 95% based on CD11b expression).
Dendritic cells were grown from bone marrow progenitor cells in the culture medium supplemented with 20 ng/ml recombinant mouse granulocyte-macrophage colony stimulating factor (GM-CSF; BioSource International, Nivelles, Belgium) for 5 days with culture medium changes on days 2 and 3. On day 5, DCs were purified using CD11c-labeled magnetic MicroBeads (Miltenyi Biotec, Bisley, Surrey, UK), according to the manufacturer's instructions (purity approximately 92% based on CD11c expression). Maturation was induced by treatment of DCs with 0.2 μg/ml lipopolysaccharide (LPS; purified by phenol extraction from Salmonella enterica, serovar typhimurium, Sigma Chemical Co.) for 24 hours.
Antigen presentation assays
Adherent macrophages at 105/well in 48 flat-well plates (Corning Limited, Artington, Surrey, UK), or mature and immature DCs at 104/well in flat-bottomed 96 well plates (Greiner Bio-One Ltd, Stonehouse, Gloucestershire, UK) were pulsed with a dilution series of CII or relevant synthetic peptides (range 40.0 to 0.02 μg/ml) for 5 hours in the absence or presence of inhibitors of uptake (10.0 μM cytochalasin D, 5.0 μM monodansylcadaverine, 1.0 mM amiloride, 0.2 mM 5-(N,N-dimethyl) amiloride (DMA) or 0.4 μg/ml filipin) for 5 hours at 37°C [28, 29]. Time and the optimal doses of APCs, antigens and inhibitors were established in separate dose-response experiments. Cells were fixed with 1.0% paraformaldehyde for 5 minutes, washed thoroughly to remove the fixative and T cell hybridoma HCII-9.1 (specific for the non-glycosylated epitope) and HCII-9.2 (specific for the glycosylated epitope) were added (5 × 104/well) and incubated for 24 hours at 37°C. Usage of synthetic peptides in all experiments controlled for the non-specific toxic effect of metabolic inhibitors and the responsiveness of T cell hybridomas. The interleukin-2 content of hybridoma supernatants was measured by bioassay as the proliferative response of the cytotoxic T cell line-2 (3 × 104/well; CTLL-2, ATCC, TIB 214, American Type Culture Collection, Rockville, MD, USA). Proliferation assays were performed by incubating popliteal lymph node cells or spleen cells (2 × 105/well) with a dilution series of CII and synthetic peptides for 72 hours, as previously described .
Cells were incubated during the last 18 hours in the presence of 14.8 kBq of [3H]thymidine (TRA310, specific activity 307 MBq/mg; Amersham International plc, Didcot, Oxfordshire, UK), harvested on glass fiber membranes and radioactivity was quantified using a direct Beta Counter (Matrix 9600, Packard Instrument Company, Meridan, CT, USA).
For testing CII-specific T cell responses in draining lymph nodes, mice were immunized in the footpad with 50 μg CII emulsified 1:1 in TiterMax adjuvant in the absence or presence of amiloride (150 μg/mouse ) and popliteal lymph nodes were removed 7 days later. Cells (2 × 105/well) were mixed with a dilution series of CII, synthetic peptides or the polyclonal T cell mitogen concanavalin A in round-bottomed 96 well plates (Corning Limited) and incubated for 4 days at 37°C in a humidified CO2 incubator. Cells were incubated during the last 18 hours in the presence of 14.8 kBq of [3H]thymidine, harvested and radioactivity was measured, as described above.
Macrophages (15 to 20 × 106 cells) were pulsed with 200 μg/ml CII for 30 minutes and chased for different periods of time. Macrophages were homogenized in buffer containing 0.25 M sucrose, 10 mM HEPES, pH 7.4 in a Dounce tissue grinder (Wheaton, Millville, NJ, USA) to obtain 80% to 85% cell lysis. Subcellular fractionation of macrophages was performed by density gradient centrifugation in 27% Percoll (Amersham plc, Little Chalfont, Buckinghamshire, UK) using a Sorvall type A-1256 fixed angle rotor (36,000 × g, 60 minutes, 4°C; Kendro Laboratory Products plc, Bishop's Stortford, Hertfordshire, UK), as described previously . Six fractions of 1.5 ml were collected manually numbered 1 to 6 from the top of the gradient. Percoll gradient fractions were each tested for β-hexosaminidase activity (marker for the presence of lysosomal enzymes) and alkaline phosphodiesterase I activity (marker for the presence of plasma membranes), as described [27, 32] The localization of markers of endosomal compartments and CII within subcellular fractions was performed by ELISA, as previously described . Briefly, 50 μl of Percoll fractions were dried in a constant flow cabinet in 96 well Microtiter® Immunoassays plates (Immulon® 1, flat bottom, Dynex Technologies, Southampton, UK). Plates were blocked in phosphate-buffered saline containing 0.05% Tween 20, 10% FBS and unlabeled anti-mouse mAb specific for FcγIIR and FcγIIIR (1:200; clone 2.4G2, Fc Block®, PharMingen, Oxford, UK) for 1 hour at room temperature. Plates were washed and incubated for 1 hour with goat anti-CII polyclonal antibody, goat anti-Rab7 and Rab9 polyclonal antibody (1: 200; Santa Cruz Biotechnology, Inc., Heidelberg, Germany). Normal goat serum was used in control experiments. After washing, plates were incubated for 1 hour with rabbit anti-goat IgG peroxidase conjugate diluted 1:1000, washed and the reaction was developed with the liquid substrate system for ELISA 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid. Absorbance was measured at 405 nm.
Bone-marrow macrophages and DCs were incubated in the absence or presence of inhibitors of uptake for five hours, and the expression of HLA-DR, CD80, CD86 and CD40 molecules was analyzed by flow cytometry, as described . Briefly, cells were incubated for 30 minutes at 4°C in Hank's balanced salt solution containing 2% FBS, 0.01 M HEPES buffer with purified anti-mouse CD16/CD32 (Fc Block®, BD-PharMingen) followed by incubation for 30 minutes at 4°C with either of the following mAb fluorescent conjugates (BD-PharMingen, Cowley, Oxford, UK): anti-HLA-DR FITC, anti-CD40 FITC, anti-CD80 PE, anti-CD86 FITC, anti-CD11c FITC, anti-CD11b FITC or isotype control, rat IgG2a PE plus IgG2b FITC. Cells were analyzed with a FACScan® flow cytometer (Becton Dickinson, Mount View, CA, USA), and 10,000 events were collected for each sample.
Bone-marrow macrophages and DCs were pulsed with 200 μg/ml CII in the absence or presence of inhibitors of uptake for 30 minutes. Transmission electron microscopy was performed as described previously . Briefly, cells were fixed in 2.5% EM grade gluteraldehyde (TAAB Lab. Equipment, Aldermaston, Berkshire, UK) diluted in 0.1 M phosphate buffer, pH 7.3, washed in phosphate buffer and post-fixed with 1% osmium tetroxide (Agar Scientific, Stansted, Essex, UK). Samples were sequentially dehydrated through a graded acetone series, impregnated with TAAB epoxy resin kit (TAAB Lab. Equipment) and polymerized at 60°C for 24 hours. Blocks were thin sectioned (80 nm), stained with uranyl acetate and lead citrate (Leica UK Ltd, Milton Keynes, UK), and examined with a Philips CM 100 (Compustage) Transmission Electron microscope (Philips Electron Optics, Eindhoven, The Netherlands). Sections through several planes of more than 50 APCs were examined for each treatment.
Bone-marrow macrophages and DCs were pulsed with 200 μg/ml CII in the absence or presence of 1.0 mM amiloride for 30 minutes at 37°C. Cytospins were prepared by centrifugation of 2 × 104 cells in 200 μl in a Shandon Cytospin 3 cytocentrifuge (Thermo Electron Corp., Waltham, MA, USA). The slides were air-dried at room temperature for 30 minutes, fixed in acetone for 10 minutes at room temperature and permeabilized in 0.1% Triton X-100 in PBS for 15 minutes at 4°C. After washing (10 mM TRIS HCl pH 7.6, containing 150 mM NaCl, TBS buffer) and blocking (normal rabbit serum 1:5 in TBS buffer, 1 hour at room temperature) staining was performed with goat anti-human CII polyclonal antibodies (1:100 in TBS buffer, 4°C, 18 hours; Santa Cruz Biotechnology, Inc.). Slides were washed and incubated with rabbit anti-goat IgG-FITC (1:100, 2 hours, room temperature, in the dark). After washing, slides were mounted in aqueous fluorescent mounting medium (DAKO Cytomation, Carpenteria, CA, USA). Confocal microscopy was performed at the BioImaging facility, University of Newcastle upon Tyne, using Leica TCS SP2 UV laser scanning confocal microscope (Leica Microsystems GmbH, Heidelberg, Germany) equipped with Time 63 oil immersion 1.32 No Plan A Pro lens. Images were acquired using the 488 excitation laser and emission was detected between 500 and 560 nm. Images were collected using 0.5 μm Z-steps and these were projected using maximal projection and overlaid with single optimized transmitted light images. In the control, cells were incubated in the absence of CII, stained and imaged at the same gain and offset levels as the positive cells and no fluorescence was observed.
Mechanisms of CII uptake in macrophages and DCs
Subcellular localization of CII after uptake
Macrophages were pulsed with 200 μg/ml CII for 30 minutes and chased for different periods of time. Following subcellular fractionation, the distribution of intracellular CII was measured by ELISA (Figure 4b). The intracellular level of CII peaked 3 hours after pulse and returned to the baseline after 24 hours. After internalization, CII was detected in Percoll fractions 3 and 4 with intermediate density co-localizing with Rab7 and Rab9 late endosomal markers. These pulse-chase experiments showed that after uptake CII was present for about five hours in membrane fractions corresponding to late endosomes, after which the level of intracellular CII dropped, probably due to terminal lysosomal transport and degradation.
We addressed the route of CII uptake into late endosomes in pulse-chase experiments in the presence of inhibitors of uptake. Pretreatment of macrophages with cytochalasin D or amiloride reduced accumulation of CII in fractions 3 and 4 (Figure 4c). Monodansylcadaverine and filipin had no effect on CII internalization (Figure 4d), consistent with data from electron microscopy (Figure 2c,d) and suggests internalization of CII primarily by macropinocytosis.
Effect of uptake on activation of CII-specific T cells in vitro
We studied whether prevention of CII uptake by DCs and macrophages results in down-regulation of antigen presentation and inhibits activation of CII-specific T cells in in vitro antigen presentation assays. Since T cells specific for the glycosylated and non-glycosylated CII have been demonstrated in peripheral blood of RA patients [44, 45], T cell hybridomas HCII-9.2, specific for the glycosylated C259–273 epitope, and HCII-9.1, specific for the non-glycosylated form of the same epitope, were used in this study .
The effect of amiloride in vivo
We studied the mechanisms of uptake of CII by macrophages and DCs for presentation to T cells specific for the arthritogenic epitope CII259–273. Electron microscopy and antigen presentation to CII259–273-specific T and presentation cell hybridomas demonstrated that uptake of CII by both types of APCs depended on actin polymerisation (cytochalasin D-sensitive) and membrane ruffling (amiloride-sensitive), suggesting the principal route was macropinocytosis. Previous electron microscopy studies showed that fibroblasts use an F-actin-dependent mechanism for CII uptake, with no distinction between phagocytosis and macropinocytosis . Macrophages have also been shown to have vacuoles containing collagen, suggesting their involvement in uptake and resorption of collagen . However, no information was available on the capacity of other cell types to take up CII, as well as on the relevance of collagen uptake to antigen presentation and specific T cell activation. We extended the electron microscopy studies with pulse-chase experiments and localization of CII by subcellular fractionation and showed that after uptake, CII accumulated in membrane fractions with intermediate density corresponding to late endosomes. Moreover, blockade of macropinocytosis prevented intracellular accumulation of CII and resulted in profound blockade of antigen presentation to T cells. The involvement of macropinocytosis in uptake of autoantigens, such as CII, by both DCs and macrophages for subsequent antigen processing and presentation to specific T cells is a novel finding. Macropinocytosis has been previously shown to deliver antigens for lysosomal processing and loading of newly synthesized MHC class II molecules in DCs [50, 51] and macrophages . This observation is in agreement with our previous report that CII is processed in lysosomal compartments of macrophages for presentation by newly synthesized MHC class II molecules .
Our model system used CD4 T cell hybridomas specific for both the glycosylated and non-glycosylated arthritogenic epitope CII259–273 generated from HLA-DR1-transgenic mice , which allowed us to test the effect of post-translational modification on uptake and presentation of CII. No differential effect of the inhibition of uptake on presentation of the glycosylated and non-glycosylated CII259–273 epitope was observed. In a previous report we showed that glycosylated and non-glycosylated forms of the same CII259–273 epitope were differentially processed in lysosomal compartments for presentation to specific CD4 T cells . Taken together, our data indicate that following macropinocytosis CII is targeted to lysosomes for antigen processing and presentation of both glycosylated and non-glycosylated epitopes to T cells. This conclusion is consistent with the presence of T cells specific for both forms of the epitope in peripheral blood of RA patients [44, 45].
The importance of our finding that blockade of CII uptake prevents activation of specific T cells in vitro was tested in vivo. We administered amiloride in vivo and showed reduction in the magnitude of CII-specific, but not polyclonal, T cell responses in draining lymph nodes, suggesting that under these experimental conditions amiloride did not directly affect the T cell response, as has been reported in other experimental settings [52, 53]. Our data suggest that amiloride caused an immunosuppressive effect on T cell activation in vivo indirectly via inhibition of uptake and antigen presentation, rather than via a direct suppression of T cell proliferation [52, 53] Amiloride has also been shown to block soluble urokinase-type plasminogen activator , a serine proteinase expressed by macrophages and DCs (our unpublished observations), suggesting another mechanism underlying the effect of this drug on antigen presentation.
The potential of immunotherapeutic protocols based on the blockade of antigen presentation has been underscored in RA, including targeting co-stimulatory or MHC class II molecules [55, 56] on APCs or T cell adhesion molecules on T cells , which has prompted the search for new ways of down-regulating antigen presentation in vivo. The results of this study suggest that interfering with antigen uptake could constitute a novel effective target for blocking antigen presentation in DCs and macrophages, as a way to prevent activation of specific CII-specific T cells. The data obtained have implications for the development of immunotherapeutic protocols for use in T cell-mediated autoimmune diseases, such as RA.
This study shows that macropinocytosis was the predominant mechanism of uptake of CII for antigen presentation by DCs and macrophages. Treatment of both professional APC types with amiloride, which prevents macropinocytosis, inhibited intracellular accumulation of CII and antigen presentation of the major arthritogenic T cell epitope in both glycosylated and non-glycosylated forms. In addition, treatment of mice with amiloride blocked the activation of collagen-specific T cells in draining lymph nodes, constituting a novel therapeutic target for the immunotherapy of RA.
= antigen-presenting cell
= type II collagen
= dendritic cell
= enzyme-linked immunosorbent assay
= fetal bovine serum
= monoclonal antibody
= major histocompatibility complex
= nuclear factor
= rheumatoid arthritis.
We thank Jan Kihlberg, Umeå University, for synthesis of galactosylated peptides, TE Cawston and Dr G McHaffie, University of Newcastle, for discussions. We also thank T Booth, BioImaging Facilitiy, University of Newcastle, for help with confocal microscopy. The work was supported by grant MP/R0619 from the Arthritis Research Campaign, UK.
- Bayry J, Thirion M, Delignat S, Misra N, Lacroix-Desmazes S, Kazatchkine MD, Kaveri SV: Dendritic cells and autoimmunity. Autoimmun Rev. 2004, 3: 183-187.View ArticlePubMedGoogle Scholar
- Holmdahl R, Tarkowski A, Jonsson R: Involvement of macrophages and dendritic cells in synovial inflammation of collagen induced arthritis in DBA/1 mice and spontaneous arthritis in MRL/lpr mice. Autoimmunity. 1991, 8: 271-280.View ArticlePubMedGoogle Scholar
- Panayi GS: B cells: a fundamental role in the pathogenesis of rheumatoid arthritis?. Rheumatology (Oxford). 2005, 44: 3-7.View ArticleGoogle Scholar
- Ludewig B, Junt T, Hengartner H, Zinkernagel RM: Dendritic cells in autoimmune diseases. Curr Opin Immunol. 2001, 13: 657-662.View ArticlePubMedGoogle Scholar
- Dittel BN, Visintin I, Merchant RM, Janeway CAJ: Presentation of the self antigen myelin basic protein by dendritic cells leads to experimental autoimmune encephalomyelitis. J Immunol. 1999, 163: 32-39.PubMedGoogle Scholar
- Leung BP, Conacher M, Hunter D, McInnes IB, Liew FY, Brewer JM: A novel dendritic cell-induced model of erosive inflammatory arthritis: distinct roles for dendritic cells in T cell activation and induction of local inflammation. J Immunol. 2002, 169: 7071-7077.View ArticlePubMedGoogle Scholar
- Sarkar S, Fox DA: Dendritic cells in rheumatoid arthritis. Front Biosci. 2005, 10: 656-665.View ArticlePubMedGoogle Scholar
- Pettit AR, Thomas R: Dendritic cells: the driving force behind autoimmunity in rheumatoid arthritis?. Immunol Cell Biol. 1999, 77: 420-427.View ArticlePubMedGoogle Scholar
- Del Nagro CJ, Kolla RV, Rickert RC: A critical role for complement C3d and the B cell coreceptor (CD19/CD21) complex in the initiation of inflammatory arthritis. J Immunol. 2005, 175: 5379-5389.View ArticlePubMedGoogle Scholar
- Holmdahl M, Vestberg M, Holmdahl R: Primed B cells present type-II collagen to T cells. Scand J Immunol. 2002, 55: 382-389.View ArticlePubMedGoogle Scholar
- O'Neill SK, Shlomchik MJ, Glant TT, Cao Y, Doodes PD, Finnegan A: Antigen-specific B cells are required as APCs and autoantibody-producing cells for induction of severe autoimmune arthritis. J Immunol. 2005, 174: 3781-3788.View ArticlePubMedGoogle Scholar
- Holmdahl M, Grubb A, Holmdahl R: Cysteine proteases in Langerhans cells limits presentation of cartilage derived type II collagen for autoreactive T cells. Int Immunol. 2004, 16: 717-726.View ArticlePubMedGoogle Scholar
- Manoury-Schwartz B, Chiocchia G, Lotteau V, Fournier C: Selective increased presentation of type II collagen by leupeptin. Int Immunol. 1997, 9: 581-589.View ArticlePubMedGoogle Scholar
- Cremer MA, Rosloniec EF, Kang AH: The cartilage collagens: a review of their structure, organization, and role in the pathogenesis of experimental arthritis in animals and in human rheumatic disease. J Mol Med. 1998, 76: 275-288.View ArticlePubMedGoogle Scholar
- Brand DD, Kang AH, Rosloniec EF: The mouse model of collagen-induced arthritis. Autoimmunity. Methods and Protocols. 2004, Totowa, NJ: Humana Press, 102: 295-312. Edited by Perl AGoogle Scholar
- Kim WU, Cho ML, Yung YO, Min SY, Park SW, Min DJ, Joon JH, Kim HY: Type II collagen autoimmunity in rheumatoid arthritis. Am J Med Sci. 2004, 327: 202-211.View ArticlePubMedGoogle Scholar
- Lu L, Woo J, Rao AS, Li Y, Watkins SC, Qian S, Starzl TE, Demetris AJ, Thomson AW: Propagation of dendritic cell progenitors from normal mouse liver using granulocyte/macrophage colony-stimulating factor and their maturational development in the presence of type-1 collagen. J Exp Med. 1994, 179: 1823-1834.View ArticlePubMedGoogle Scholar
- Hao HN, Yang SY, Wooley PH: Direct interactions of collagen II and Toll-like receptor depend upon the saccharide residue of collagen II: a potential mechanism for collagen-induced arthritis. Arthritis Rheum. 2005, 52: S477-Google Scholar
- Pribila JT, Itano AA, Mueller KL, Shimizu Y: The α1β1 and αEβ7 integrins define a subset of dendritic cells in peripheral lymph nodes with unique adhesive and antigen uptake properties. J Immunol. 2004, 172: 282-291.View ArticlePubMedGoogle Scholar
- Cremer MA, Stuart JM, Townes AS, Kang AH: Collagen-induced polyarthritis in rats: a study of native type II collagen for adjuvant activity. J Immunol. 1980, 124: 2912-2918.PubMedGoogle Scholar
- Stuart LM, Ezekowitz RAB: Phagocytosis: elegant complexity. Immunity. 2005, 22: 539-550.View ArticlePubMedGoogle Scholar
- Sansonetti PJ: Phagocytosis of bacterial pathogens: implications in the host response. Semin Immunol. 2001, 13: 381-390.View ArticlePubMedGoogle Scholar
- Kaksonen M, Toret CP, Drubin DG: A modular design for the clathrin- and actin-mediated endocytosis machinery. Cell. 2005, 123: 305-320.View ArticlePubMedGoogle Scholar
- Nichols B: Caveosomes and endocytosis of lipid rafts. J Cell Sci. 2003, 116: 4707-4714.View ArticlePubMedGoogle Scholar
- Bathori G, Cervenak L, Karadi I: Caveolae-an alternative endocytotic pathway for targeted drug delivery. Crit Rev Ther Drug Carrier Syst. 2004, 21: 67-95.View ArticlePubMedGoogle Scholar
- Holm B, Baquer SM, Holm L, Holmdahl R, Kihlberg J: Role of the galactosyl moiety of collagen glycopeptides for T-cell stimulation in a model for rheumatoid arthritis. Bioorg Med Chem. 2003, 11: 3981-3987.View ArticlePubMedGoogle Scholar
- von Delwig A, Altmann DM, Isaacs JD, Harding CV, Holmdahl R, McKie N, Robinson JH: The impact of glycosylation on HLA-DR1 restricted T cell recognition of type II collagen in a mouse model. Arthritis Rheum. 2006, 54: 482-491.View ArticlePubMedGoogle Scholar
- von Delwig A, Bailey E, Gibbs D, Robinson JH: The route of bacterial uptake by macrophages influences the repertoire of epitopes presented to CD4 T cells. Eur J Immunol. 2002, 32: 3714-3719.View ArticlePubMedGoogle Scholar
- Werling D, Hope JC, Chaplin P, Collins RA, Taylor G, Howard CJ: Involvement of caveolae in the uptake of respiratory syncytial virus antigen by dendritic cells. J Leukoc Biol. 1999, 66: 50-58.PubMedGoogle Scholar
- Delvig AA, Robinson JH, Wetzler LM: Testing meningococcal vaccines for mitogenicity and superantigenicity. Meningococcal vaccines. Methods and protocols. 2001, Totowa, NJ: Humana Press, 66: 199-221. Edited by: Pollard AJ, Maiden MCJView ArticleGoogle Scholar
- Lyons JC, Ross BD, Song CW: Enhancement of hyperthermia effect in vivo by amiloride and DIDS. Int J Radiat Oncol Biol Phys. 1993, 25: 95-103.View ArticlePubMedGoogle Scholar
- von Delwig A, Ramachandra L, Harding CV, Robinson JH: Localization of peptide/MHC class II complexes in macrophages following antigen processing of viable Streptococcus pyogenes. Eur J Immunol. 2003, 33: 2353-2360.View ArticlePubMedGoogle Scholar
- von Delwig A, Musson JA, Shim HK, Lee JJ, Walker N, Harding CV, Williamson ED, Robinson JH: Distribution of productive antigen processing activity for MHC class II presentation in macrophages. Scand J Immunol. 2005, 62: 243-250.View ArticlePubMedGoogle Scholar
- Grassme HU, Ireland RM, van Putten JPM: Gonococcal opacity protein promotes bacterial entry-associated rearrangements of the epithelial cell actin cytoskeleton. Infect Immun. 1996, 64: 1621-1630.PubMed CentralPubMedGoogle Scholar
- West MA, Bretscher MS, Watts C: Distinct endocytotic pathways in epidermal growth factor-stimulated human carcinoma A431 cells. J Cell Biol. 1989, 109: 2731-2739.View ArticlePubMedGoogle Scholar
- Valentin-Weigand P, Benkel P, Rohde M, Chhatwal GS: Entry and intracellular survival of group B Streptococci in J774 macrophages. Infect Immun. 1996, 64: 2467-2473.PubMedGoogle Scholar
- Harris J, Werling D, Hope JC, Taylor G, Howard CJ: Caveolae and caveolin in immune cells: distribution and functions. Trends Immunol. 2002, 23: 158-164.View ArticlePubMedGoogle Scholar
- Tsark EC, Wang W, Teng YC, Arkfeld D, Dodge GR, Kovats S: Differential MHC class II-mediated presentation of rheumatoid arthritis autoantigens by human dendritic cells and macrophages. J Immunol. 2002, 169: 6625-6633.View ArticlePubMedGoogle Scholar
- Graham JM: Subcellular fractionation and isolation of organelles. Isolation of lysosomes from tissues and cells by differential and density gradient centrifugation. Current Protocols in Cell Biology. Edited by: Bonifacino JS, Dasso M, Hartford JB, Lippincott-Schwartz J, Yamada KM. 2000, New York: John Wiley & Sons, Inc, 1-21.Google Scholar
- Peters PJ, Neefjes JJ, Oorschot V, Ploegh HL, Geuze HJ: Segregation of MHC class II molecules from MHC class I molecules in the Golgi complex for transport to lysosomal compartments. Nature. 1991, 349: 669-676.View ArticlePubMedGoogle Scholar
- Jordens I, Marsman M, Kuijl C, Neefjes JJ: Rab proteins, connecting transport and vesicle fusion. Traffic. 2005, 6: 1070-1077.View ArticlePubMedGoogle Scholar
- Bertram EM, Hawley RG, Watts TH: Overexpression of rab7 enhances the kinetics of antigen processing and presentation with MHC class II molecules in B cells. Int Immunol. 2002, 14: 309-318.View ArticlePubMedGoogle Scholar
- Zerial M, McBride H: Rab proteins as membrane organizers. Nat Rev Mol Cell Biol. 2001, 2: 107-117.View ArticlePubMedGoogle Scholar
- Kim HY, Kim WU, Cho ML, Lee SK, Joun J, Kim SI, Yoo WH, Park JH, Min JK, Lee SH, Park SH, Cho CS: Enhanced T cell proliferative response to type II collagen and synthetic peptide CII (255–274) in patients with rheumatoid arthritis. Arthritis Rheum. 1999, 42: 2085-2093.View ArticlePubMedGoogle Scholar
- Bäcklund J, Carlsen S, Hoger T, Holm B, Fugger L, Kihlberg J, Burkhardt H, Holmdahl R: Predominant selection of T cells specific for the glycosylated collagen type II epitope (263–270) in humanized transgenic mice and in rheumatoid arthritis. Proc Natl Acad Sci USA. 2002, 99: 9960-9965.PubMed CentralView ArticlePubMedGoogle Scholar
- Haddad JJ: Amiloride and the regulation of NF-κB: an unsung crosstalk and missing link between fluid dynamics and oxidative stress-related inflammation – controversy or pseudo-controversy?. Biochem Biophys Res Commun. 2005, 327: 373-381.View ArticlePubMedGoogle Scholar
- Cuschleri J, Gourlay D, Garcia I, Jelacic S, Maier RV: Endotoxin-induced endothelial cell proinflammatory phenotypic differentiation requires stress fiber polymerization. Shock. 2003, 19: 433-439.View ArticlePubMedGoogle Scholar
- Everts V, van der Zee E, Creemers LB, Beersten W: Phagocytosis and intracellular digestion of collagen, its role in turnover and remodelling. Histochem J. 1996, 28: 229-245.View ArticlePubMedGoogle Scholar
- Parakkal PF: Involvement of macrophages in collagen resorption. J Cell Biol. 1969, 41: 345-354.PubMed CentralView ArticlePubMedGoogle Scholar
- Inaba K, Inaba M: Antigen recognition and presentation by dendritic cells. Int J Hematol. 2005, 81: 181-187.View ArticlePubMedGoogle Scholar
- Sallusto F, Cella M, Danieli C, Lanzavecchia A: Dendritic cells use macropinocytosis and the mannose receptor to concentrate macromolecules in the major histocompatibility complex class II compartment: downregulation by cytokines and bacterial products. J Exp Med. 1995, 182: 389-400.View ArticlePubMedGoogle Scholar
- Tang CM, Presser F, Morad M: Amiloride selectively blocks the low threshold (T) calcium channel. Science. 1988, 240: 213-215.View ArticlePubMedGoogle Scholar
- Lai ZF, Chen YZ, Nishimura Y, Nishi K: An amiloride-sensitive and voltage-dependent Na+ channel in an HLA-DR-restricted human T cell clone. J Immunol. 2000, 165: 83-90.View ArticlePubMedGoogle Scholar
- Dyer KD, Linz-Mcgillem LA, Alliegro MA, Alliegro MC: Receptor-bound uPA is reversibly protected from inhibition by low molecular weight inhibitors. Cell Biol Int. 2002, 26: 327-335.View ArticlePubMedGoogle Scholar
- Liossis SN, Sfikakis PP: Costimulation blockade in the treatment of rheumatic diseases. BioDrugs. 2004, 18: 95-102.View ArticlePubMedGoogle Scholar
- Falcioni F, Ito K, Vidovic D, Belunis C, Campbell R, Berthel SJ, Bolin DR, Gillespie PB, Huby N, Olson GL, et al: Peptidomimetic compounds that inhibit antigen presentation by autoimmune disease-associated class II major histocompatibility molecules. Nat Biotechnol. 1999, 17: 562-567.View ArticlePubMedGoogle Scholar
- Zeyda M, Poglitsch M, Geyeregger R, Smolen JS, Zlabinger GJ, Hörl WH, Waldhäusl W, Stulnig TM, Säemann MD: Disruption of the interaction of T cells with antigen-presenting cells by the active leflunomide metabolite teriflunomide: involvement of impaired integrin activation and immunologic synapse formation. Arthritis Rheum. 2005, 52: 2730-2739.View ArticlePubMedGoogle Scholar
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