el-Zaatari F A, Taurog J D
Harold C. Simmons Arthritis Research Center, University of Texas Southwestern Medical Center, Dallas 75235-8884.
Hum Immunol. 1992 Apr;33(4):243-8. doi: 10.1016/0198-8859(92)90331-g.
The consensus HLA-B27 sequence includes a unique constellation of amino acid residues along the peptide-binding cleft. To investigate the potential role of this region in the antigenic structure of HLA-B27, a panel of transfected cell lines was produced expressing 24 mutant B27 molecules with single or multiple substitutions within this constellation of residues. The cells were analyzed by flow cytometry with a panel of four anti-B27 mAb: ME1, GSP5.3, GS145.2, and B27M2. Previous studies have suggested that position 67 exerts a conformational effect on the ME1, GSP5.3, and GS145.2 epitopes. This was further supported in these studies by the observation that additional substitutions at the flanking residues 63 and 70 could reverse the disruption of these mAb epitopes by large residues at 67. Substitutions at positions 69-71 disrupted the binding of ME1 and GSP5.3, apparently by a direct effect. Individual substitutions at either of the two positions bearing residues unique to B27, 70 and 97, had no significant influence on the binding of any of the four mAb. The region of amino acid positions 63-71 in HLA-B27 thus appears to participate in the formation of at least three distinct epitopes shared by B27 and B7, identified by ME1, GSP5.3, and GS145.2.
HLA - B27的共有序列在肽结合裂隙处包含一组独特的氨基酸残基。为了研究该区域在HLA - B27抗原结构中的潜在作用，构建了一组转染细胞系，这些细胞系表达了24种突变的B27分子，这些分子在这组残基内有单个或多个替换。用一组四种抗B27单克隆抗体（ME1、GSP5.3、GS145.2和B27M2）通过流式细胞术对这些细胞进行分析。先前的研究表明，67位氨基酸对ME1、GSP5.3和GS145.2表位有构象影响。在这些研究中，63和70位侧翼残基的额外替换能够逆转67位大残基对这些单克隆抗体表位的破坏，这进一步支持了上述观点。69 - 71位的替换破坏了ME1和GSP5.3的结合，显然是通过直接作用。B27特有的两个残基位置70和97中的任何一个位置的单个替换，对四种单克隆抗体中任何一种的结合都没有显著影响。因此，HLA - B27中63 - 71位氨基酸区域似乎参与了至少三种由B27和B7共享的不同表位的形成，这些表位由ME1、GSP5.3和GS145.2鉴定。
