title: Localization of MHC class II/human cartilage glycoprotein-39 complexes in synovia of rheumatoid arthritis patients using complex-specific monoclonal antibodies.
abstract: Recently human cartilage gp-39 (HC gp-39) was identified as a candidate autoantigen in rheumatoid arthritis (RA). To further investigate the relevance of this Ag in RA, we have generated a set of five mAbs to a combination epitope of complexes of HC gp-39(263-275) and the RA-associated DR alpha beta 1*0401 HLA class II molecules. FACS studies revealed that these mAb recognize specific complexes on homozygous DR alpha beta 1*0401-positive B lymphoblastoid cells pulsed with HC gp-39(263-275). The best mAb, 12A, was further characterized using a set of irrelevant DR alpha beta 1*0401-binding peptides and truncated/elongated versions of HC gp-39(263-275) itself. The minimal epitope recognized in combination with DR alpha beta 1*0401 was HC gp-39(263-273). Peptides not encompassing HC gp-39(263-273) were not recognized. Three of five mAb were able to inhibit (up to 90%) the response of HC gp-39(263-275)-specific DR alpha beta 1*0401-restricted T cell hybridomas to peptide-pulsed APC or purified complexes. Using mAb 12A, we have been able to identify and localize dendritic cells that present DR alpha beta 1*0401/HC gp-39(263-275) complexes in synovial tissue of DR alpha beta 1*0401-positive RA patients, indicating local presentation of the HC gp-39(263-275) epitope in the inflamed target tissue by professional APC. These data support a role of HC gp-39 in the local autoimmune response that leads to chronic inflammation and joint destruction.
authors.affiliation: Department of Pharmacology, N. V. Organon, Oss, The Netherlands. peter.steembakkers@organon.com
authors.forename: Peter G A
authors.initials: PG
authors.lastname: Steenbakkers
authors.forename: Dominique
authors.initials: D
authors.lastname: Baeten
authors.forename: Eric
authors.initials: E
authors.lastname: Rovers
authors.forename: Eric M
authors.initials: EM
authors.lastname: Veys
authors.forename: Antonius W M
authors.initials: AW
authors.lastname: Rijnders
authors.forename: Jan
authors.initials: J
authors.lastname: Meijerink
authors.forename: Filip
authors.initials: F
authors.lastname: De Keyser
authors.forename: Annemieke M H
authors.initials: AM
authors.lastname: Boots
mesh_terms: D054392:Adipokines; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000378:metabolism* / Q000494:pharmacology; D000918:Antibody Specificity; D017951:Antigen Presentation; D000938:Antigen-Presenting Cells / Q000276:immunology / Q000378:metabolism; D001172:Arthritis, Rheumatoid / Q000276:immunology / Q000378:metabolism*; D001324:Autoantigens / Q000276:immunology / Q000378:metabolism*; D016175:B-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D002461:Cell Line, Transformed; D000071451:Chitinase-3-Like Protein 1; D000939:Epitopes / Q000276:immunology / Q000378:metabolism*; D005260:Female; D006023:Glycoproteins / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D006684:HLA-DR Antigens / Q000276:immunology / Q000378:metabolism*; D059811:HLA-DRB1 Chains; D006801:Humans; D006825:Hybridomas; D007166:Immunosuppressive Agents / Q000494:pharmacology; D037102:Lectins; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D010446:Peptide Fragments / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism; D013583:Synovial Membrane / Q000276:immunology / Q000378:metabolism*
chemical_list: D054392:Adipokines; D000911:Antibodies, Monoclonal; D001324:Autoantigens; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D000939:Epitopes; D006023:Glycoproteins; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D007166:Immunosuppressive Agents; D037102:Lectins; D010446:Peptide Fragments