Forero L, Zwirner N W, Fink C W, Fernández-Viña M A, Stastny P
Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235-8886, USA.
Hum Immunol. 1998 Jul;59(7):443-50. doi: 10.1016/s0198-8859(98)00034-2.
Previous studies have shown that susceptibility to Pauciarticular Juvenile Arthritis is associated with HLA-A0201. Recently, autoantibodies against the protein of the DEK oncogene have been found in sera of patients with this disease. If T cells are involved in the pathogenesis of joint lesions, it is possible that they target autoantigens presented by HLA-A0201. Therefore, we investigated whether DEK-derived peptides can bind efficiently to HLA-A0201. Nonameric peptides selected considering anchor positions 2 and 9, and preferred amino acids at other positions, were incubated either with the human TAP-deficient cell line 174CEM.T2 (T2) or with the homozygous B cell line JESTHOM (A0201, B2705, Cw1), previously depleted of endogenous peptides. Binding was measured as the increase of detection of fully assembled, HLA-A0201 molecules by flow cytometry with the anti-HLA-A2 monoclonal antibody (mAb) BB7.2. Three out of ten selected DEK-derived peptides showed binding to HLA-A0201, which was peptide concentration-dependent (1 microM to 100 microM). DEK155-163 (AMLKSICEV), which also has two preferred amino acid residues at positions 6 and 8, yielded the highest binding. DEK163-171 (VLDLERSGV) and DEK72-80 (SLQREPFTI), which also has one preferred amino acid residue at position 8, also were able to bind to HLA-A0201. Furthermore, peptide-induced, fully assembled, HLA-A0201 molecules were immunoprecipitated with the BB7.2 mAb from metabolically-labeled T2 cells incubated with DEK72-80, DEK155-163, and DEK163-171. A faint band was observed in the immunoprecipitates of cells incubated with DEK65-73 (it carries a preferred amino acid residue at position 6), suggesting that this peptide interacts weakly with HLA-A0201. These results indicate that several nonameric peptides derived from the DEK protein can bind to HLA-A 0201 and suggest that the complexes formed may be able to stimulate CD8+ T cells in patients with Pauciarticular Juvenile Arthritis.
先前的研究表明，少关节型幼年特发性关节炎易感性与HLA - A0201相关。最近，在该疾病患者的血清中发现了针对DEK癌基因蛋白的自身抗体。如果T细胞参与关节病变的发病机制，那么它们有可能以HLA - A0201提呈的自身抗原为靶点。因此，我们研究了DEK衍生肽是否能有效结合HLA - A0201。考虑到第2和第9位锚定位点以及其他位置的优选氨基酸而选择的九聚体肽，与人类TAP缺陷细胞系174CEM.T2（T2）或预先去除内源性肽的纯合B细胞系JESTHOM（A0201，B2705，Cw1）一起孵育。通过用抗HLA - A2单克隆抗体（mAb）BB7.2进行流式细胞术检测完全组装的HLA - A0201分子的增加来测量结合情况。所选择的十条DEK衍生肽中有三条显示出与HLA - A0201结合，且这种结合呈肽浓度依赖性（1微摩尔至100微摩尔）。DEK155 - 163（AMLKSICEV）在第6和第8位也有两个优选氨基酸残基，其结合能力最强。DEK163 - 171（VLDLERSGV）和DEK72 - 80（SLQREPFTI）在第8位也有一个优选氨基酸残基，它们也能够结合HLA - A0201。此外，用DEK72 - 80、DEK155 - 163和DEK163 - 171孵育的代谢标记T2细胞中，肽诱导的、完全组装的HLA - A0201分子用BB7.2 mAb进行免疫沉淀。在用DEK65 - 73孵育的细胞免疫沉淀物中观察到一条 faint 条带（它在第6位带有一个优选氨基酸残基），这表明该肽与HLA - A0201的相互作用较弱。这些结果表明，源自DEK蛋白的几种九聚体肽可以结合HLA - A 0201，并提示所形成的复合物可能能够刺激少关节型幼年特发性关节炎患者的CD8 + T细胞。
