Verreck F A, Elferink D, Vermeulen C J, Amons R, Breedveld F, de Vries R R, Koning F
Department of Immunohaematology and Bloodbank, University Hospital Leiden, The Netherlands.
Tissue Antigens. 1995 Apr;45(4):270-5. doi: 10.1111/j.1399-0039.1995.tb02451.x.
Rheumatoid arthritis (RA) occurs more frequently in HLA-DR4+ individuals than in those who do not express this MHC class II molecule. Although the role of this genetic factor in the immunopathology of this autoimmune disease is unclear, the association of RA with HLA-DR4 may indicate that DR4 molecules present autoantigen(s) to T cells. Here we report the analysis of naturally processed peptides, eluted from a mixture of HLA-DR4Dw4 (DRB10401) and DR53 (DRB40101) molecules isolated from an RA patient-derived EBV-transformed B cell line. Several (size variants of) self-peptides originating from the autologous molecules HLA-A2, HLA-Cw9, HLA-B62, HLA-DR4Dw4 and HLA-DR53, were identified. We also found a sequence that has no homology to any protein in the SwissProt protein sequence databank, and a peptide identical to an internal fragment of the autoantigen calreticulin. The association of the identified peptides with cells expressing HLA-DR4Dw4/DR53 was confirmed by peptide binding analysis. In agreement with previously described peptide binding motifs for DR4Dw4, most peptides contained an aromatic residue (Phe, Tyr, Trp) at relative position i and a small hydroxyl-containing residue (Ser, Thr) at i + 5. Our findings indicate that in RA patient-derived EBV-transformed B cells DR4Dw4/DR53 molecules present a peptide from the autoantigen calreticulin. Interestingly, autoantibodies against calreticulin have been found in various rheumatic diseases, including rheumatoid arthritis. Thus, the analysis of HLA class II-bound peptides can lead to the identification of putative T helper epitopes, which might be involved in the immunopathology of autoimmune diseases.
类风湿性关节炎（RA）在HLA - DR4阳性个体中的发生率高于不表达这种II类主要组织相容性复合体分子的个体。尽管这种遗传因素在这种自身免疫性疾病的免疫病理学中的作用尚不清楚，但RA与HLA - DR4的关联可能表明DR4分子将自身抗原呈递给T细胞。在此，我们报告了对从一名RA患者来源的EB病毒转化B细胞系中分离出的HLA - DR4Dw4（DRB10401）和DR53（DRB40101）分子混合物中洗脱的天然加工肽的分析。鉴定出了几种源自自身分子HLA - A2、HLA - Cw9、HLA - B62、HLA - DR4Dw4和HLA - DR53的自身肽（及其大小变体）。我们还发现了一个在SwissProt蛋白质序列数据库中与任何蛋白质都无同源性的序列，以及一个与自身抗原钙网蛋白的内部片段相同的肽。通过肽结合分析证实了所鉴定的肽与表达HLA - DR4Dw4/DR53的细胞的关联。与先前描述的DR4Dw4肽结合基序一致，大多数肽在相对位置i处含有一个芳香族残基（苯丙氨酸、酪氨酸、色氨酸），在i + 5处含有一个小的含羟基残基（丝氨酸、苏氨酸）。我们的研究结果表明，在RA患者来源的EB病毒转化B细胞中，DR4Dw4/DR53分子呈递来自自身抗原钙网蛋白的一种肽。有趣的是，在包括类风湿性关节炎在内的各种风湿性疾病中都发现了针对钙网蛋白的自身抗体。因此，对II类HLA结合肽的分析可以导致鉴定出可能参与自身免疫性疾病免疫病理学的假定T辅助表位。
