Lang Jianshe, Zhan Jinbiao, Xu Linhai, Yan Zhikun
Department of Biochemistry, Zhejiang University Medical School, Hangzhou 310006, China.
Biochem Biophys Res Commun. 2006 May 26;344(1):214-20. doi: 10.1016/j.bbrc.2006.03.112.
The prevention of hyperacute rejection (HAR) triggered by interaction between the human natural antibody and xenoreactive antigenic epitope (Gal-alpha1, 3Gal) present on pig cells is the key to success in pig-to-human xenotransplantation. The phage display technology offers an effective strategy for screening peptides which can interact with the anti-Gal antibody to block alpha-Gal antigen binding site. Two peptide libraries, linear 7 peptide library and C7C library, were panned on the anti-B monoclonal antibody which has the characteristic of binding to the alpha-Gal antigenic epitope. After four rounds of panning, 22 positive phage clones were selected. Highly homologous sequence PT and STL existed among these selected peptides. Stachyose competitive ELISAs revealed that these peptides specifically bound to alpha-Gal antigen binding site. Eight peptide mimics of alpha-Gal antigenic epitope could inhibit the agglutination of pig red blood cells mediated by human sera in a dose-dependent manner. These results demonstrated that the selected peptides can mimic the conformational structure of alpha-Gal antigenic epitope and have the therapeutic potential in xenotransplantation.
预防由人类天然抗体与猪细胞上存在的异种反应性抗原表位（Gal-α1,3Gal）之间的相互作用引发的超急性排斥反应（HAR）是猪到人的异种移植成功的关键。噬菌体展示技术为筛选能够与抗Gal抗体相互作用以阻断α-Gal抗原结合位点的肽提供了一种有效策略。在具有与α-Gal抗原表位结合特性的抗B单克隆抗体上淘选了两个肽库，即线性7肽库和C7C库。经过四轮淘选，选择了22个阳性噬菌体克隆。在这些选定的肽中存在高度同源的序列PT和STL。水苏糖竞争性酶联免疫吸附测定表明这些肽特异性结合α-Gal抗原结合位点。α-Gal抗原表位的八个肽模拟物能够以剂量依赖的方式抑制人血清介导的猪红细胞凝集。这些结果表明，选定的肽可以模拟α-Gal抗原表位的构象结构，并且在异种移植中具有治疗潜力。
