摘要
目的 研究人类白细胞抗原 (HLA) DRβ1特异性Ⅱ型胶原 (CII)多肽的T细胞受体(TCR)结合表位改变对T细胞激活的影响。探讨通过抑制T细胞对抗原肽的识别治疗类风湿关节炎的新途径。方法 利用AutoDock3 0系统设计非T细胞结合肽 ;以激光共焦显微镜及流式细胞仪观察荧光标记的CⅡ 2 6 3 2 72修饰肽的细胞内转运及其在细胞膜上的表达 ;应用HLA DR1转基因抗原呈递细胞和特异性T细胞的激活体系 ,研究替换TCR识别氨基酸的CII修饰肽在T细胞激活中的作用。结果 计算机模拟显示CII第 2 6 3位苯丙氨酸 (F)、2 6 6位谷氨酸 (E)是与HLA DR1结合的关键位点 ,而 2 6 7位谷氨酰胺 (Q)、2 6 9位脯氨酸 (P)和 2 70位赖氨酸 (K)是T细胞识别的主要功能氨基酸。用甘氨酸 (G)、和 /或丙氨酸 (A)替换上述位点可去除功能性侧链。CⅡ修饰肽可被HLA DR1转基因抗原呈递细胞摄取并与膜表面的HLA DR1分子结合。CⅡ 2 6 3 2 72原型肽可激活T细胞 ,而用A或G单一替换 2 6 7、2 6 8、2 6 9、2 70位氨基酸或连续替换 2 6 8 2 70位氨基酸的修饰肽对T细胞的激活能力明显降低 (P <0 0 1)。低反应性修饰肽 2 70A、sub2 6 8 2 70对CⅡ诱导的T细胞激活有显著抑制作用。结论 通过替换CII中TCR特异性氨基酸可减弱或消除其对T细胞的结合能力及激?
Objective To evaluate the inhibitory effect of human leukocyte antigen (HLA) DRβ1 specific collagen II (CII) peptides with substitutions of TCR binding residues on T cell activation, and explore a new therapeutic strategy for T cell mediated autoimmune diseases by interfering with antigen recognition of T Cell receptor (TCR) Methods Non TCR binding peptides were designed by computer modeling based on interaction of HLA DR1 The modified CII 263 272 Intracellular transfer of the modified CII peptide and its binding to HLA DR1 were studied using confocal microscopy and fluorescence activated cell sorter (FACS) The effects of altered peptides on T cell activation were evaluated using an antigen presenting system consisting of HLA DR1 transgenic APC and CII specific T cells Results Computer modeling showed the side chains of 263 (F), 266 (E) fit in the peptide binding groove, and form hydrogen bond with α1, β1 chain of HLA DR1 The side chains of TCR specific 267(Q) and 270 (K) protruded out of the groove, which might be TCR recognizing residues The modified CII peptides with intact HLA DR1 binding residues were bound to intracellular HLA DR1 and expressed on cell surface The modified peptides with single residue substitution of 267 270 and consecutive substitution of 268 270 showed a hyporesponsive T cell activation Altered peptides 270A, sub268 270 could significantly suppress the T cell activation induced by CII263 272 Conclusion The altered peptides with substitution of TCR binding residues are hyporesponsive in T cell activation, and may competitively inhibit the T cell activation in T cell mediated autoimmune diseases
出处
《中华医学杂志》
CAS
CSCD
北大核心
2003年第17期1505-1509,共5页
National Medical Journal of China
基金
国家自然科学基金 (3 9970 697)
国家杰出青年基金(3 0 0 2 5 0 40 )资助
