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Logo of arthrestherBioMed Centralbiomed central web sitesearchsubmit a manuscriptregisterthis articleArthritis Research & Therapy
Arthritis Res Ther. 2006; 8(4): R93.
Published online May 16, 2006. doi:  10.1186/ar1964
PMCID: PMC1779380
Inhibition of macropinocytosis blocks antigen presentation of type II collagen in vitro and in vivo in HLA-DR1 transgenic mice
Alexei von Delwig,corresponding author1 Catharien MU Hilkens,1 Daniel M Altmann,2 Rikard Holmdahl,3 John D Isaacs,1 Clifford V Harding,4 Helen Robertson,5 Norman McKie,1 and John H Robinson1
1Musculoskeletal Research Group, Clinical Medical Sciences, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, UK
2Human Disease Immunogenetics Group, Department of Infectious Diseases, Imperial College School of Medicine, Hammersmith Hospital, London, UK
3Department of Cell and Molecular Biology, Lund University, Lund, Sweden
4Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
5BioImaging Facility, Clinical Laboratory Sciences, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, UK
corresponding authorCorresponding author.
Alexei von Delwig: alexei.delwig/at/; Catharien MU Hilkens: Catharien.Hilkens/at/; Daniel M Altmann: d.altmann/at/; Rikard Holmdahl: rikard.holmdahl/at/; John D Isaacs: J.D.Isaacs/at/; Clifford V Harding: cvh3/at/; Helen Robertson: helen.robertson/at/; Norman McKie: norman.mckie/at/; John H Robinson: j.h.robinson/at/
Received February 16, 2006; Revisions requested March 27, 2006; Revised April 13, 2006; Accepted April 24, 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.
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