B.-Y. Diab 7 N.C. Lambert 7 F.-E. L’Faqihi P. Loubet-Lescoulié 7 C. de Préval 7 H. Coppin (Y) 1 U. 395 INSERM, IFR 30 “INSERM-UPS-CNRS-CHU”, CHU Purpan, F-31300 Toulouse, France Present address: 1 CNRS/UPCM, ERS 1590, IFR 30 “INSERM-UPS-CNRS-CHU”, CHU Purpan, F-31300 Toulouse, France Immunogenetics (1999) 49 : 36–44 Q Springer-Verlag 1999 ORIGINAL PAPER Bader-Yassine Diab 7 Nathalie C. Lambert Fatima-Ezzahra L’Faqihi 7 Patrick Loubet-Lescoulié Claude de Préval 7 Hélène Coppin Human collagen II peptide 256–271 preferentially binds to HLA-DR molecules associated with susceptibility to rheumatoid arthritis Received: 6 May 1998 / Revised: 16 July 1998 Abstract The binding ability of 23 overlapping pep- tides, all derived from the CB11 fragment of CII, was tested on several HLA-DR molecules associated or not with disease susceptibility. These experiments were performed on a variety of cells expressing different HLA-DR molecules, using both indirect and direct binding assays. The CII (256–271) fragment was shown to bind to a restricted population among which the HLA-DR molecules associated with susceptibility to rheumatoid arthritis. The results also clearly indicate that the binding specificity of CII (256–271), among the DR4 molecules, is controlled by the nature of the HLA-DR molecule b-chain residues 71 and 74, resi- dues previously shown by X-ray crystallography to be involved in the HLA-DR/peptide interaction. The hu- man CII (256–271) peptide is thus likely to play a role in the disease process. Key words Rheumatoid arthritis 7 Collagen II 7 Peptide 7 Binding Introduction Rheumatoid arthritis (RA) is an autoimmune disease believed to be initiated by the dysfunction of the pe- ripheral tolerance associated with the recognition of self proteins secluded in peripheral joints. The target autoantigens involved in RA have not yet been identif- ied. Several antigens derived from heat shock proteins or proteins specific for the peripheral joints, such as proteoglycans and type II or type XI collagens, are re- cognized by the synovial T cells in the context of self class II molecules. Several lines of evidence point to type II collagen as a significant autoantigen associated with the development of RA: autoantibodies directed against type II collagen (CII) are found in the serum and joint fluid of a significant proportion of RA pa- tients (Banerjee et al. 1988; Choi et al. 1988; Clague et al. 1983; Rowley et al. 1987; Trentham et al. 1981), cells obtained from the affected synovium of RA patients re- cognize type II collagen (Elkayam et al. 1991; Londei et al. 1989), and oral administration of chicken collagen to patients and of human collagen to mice significantly im- proves RA and collagen-induced arthritis (CIA), re- spectively (Khare et al. 1995; Trentham et al. 1993). Moreover, it is possible to induce a chronic arthritis in genetically susceptible strains of mice, rats, and rhesus- monkeys, by immunization with a preparation of heter- ologous type II collagen (Griffiths et al. 1981; Holm- dahl et al. 1990; Holmdahl et al. 1995; Trentham et al. 1977; Yoo et al. 1988) and it has been shown that DR1 transgenic mice immunized with human CII develop- ped arthritis. The auto immune response in that case was mostly directed against the immunodominant epi- tope 262–270 (Rosloniec et al. 1997). It is established that both environmental and genetic factors are involved in the initiation and perpetuation of the disease in human. The association of several DR alleles with the susceptibility to RA has been reported in a number of studies. These HLA-DR alleles differ between populations: HLA-DR alleles DRB1*0101, *0401, and *0404 are predominantly associated with the disease in Caucasians, DRB1*0405 in Japanese, DRB1*0101 in Israeli Jews, DRB1*1001 in a Spanish population, and DRB1*1402 in Yakima Indians (Deighton et al. 1993; Gao et al. 1991; Ohta et al. 1982; Sanchez et al. 1990; Wilkens et al. 1991). It has been proposed that particular HLA-DR molecules specifica- lly present pathogenic self peptides. Several amino acids are shared by the RA-associated DR molecules (Gregersen et al. 1987). These amino acids are located