Jensen-jarolim E, Leitner A, Kalchhauser H, Zürcher A, Ganglberger E, Bohle B, Scheiner O, Boltz-nitulescu G, Breiteneder H
Department of General and Experimental Pathology, University of Vienna, Austria.
FASEB J. 1998 Dec;12(15):1635-42. doi: 10.1096/fasebj.12.15.1635.
The major birch pollen allergen Bet v 1 is one of the most extensively characterized allergens both on the molecular and the immunological level. To define conformational B cell epitopes on Bet v 1, we screened filamentous phage libraries expressing circular or linear nonapeptides to select ligands specific for anti-Bet v 1 murine monoclonal antibodies BIP1 and BIP4. The deduced amino acid sequence of the BIP1 ligand was CFPYCYPSESA, and of the BIP4-ligand, CRQTRTMPGC. Both sequences derived from the circular phage library. Alignments to the sequence of Bet v 1 showed no similarities, indicating that the antibodies most likely recognize discontinuous epitopes. Phages displaying these mimotopes were capable of inhibiting interactions of the anti-Bet v 1 monoclonals with Bet v 1 in a dose-dependent manner in ELISA. In contrast, sequence-identical synthetic peptides were ineffective in blocking the antibody-allergen interactions. This is in agreement with the conformational inhomogeneity of the peptides in solution as observed by nuclear magnetic resonance spectroscopy. Intragastric administration of phages expressing the BIP1 mimotope induced a Bet v 1-specific IgG response in Balb/c mice. We conclude that peptide mimotopes, when displayed on phages, may induce a protective IgG response preventing IgE-mediated allergic reactions, suggesting a possible clinical application.
主要的桦树花粉过敏原Bet v 1是在分子和免疫水平上特征最为明确的过敏原之一。为了确定Bet v 1上的构象性B细胞表位，我们筛选了表达环状或线性九肽的丝状噬菌体文库，以选择对抗Bet v 1鼠单克隆抗体BIP1和BIP4具有特异性的配体。BIP1配体推导的氨基酸序列为CFPYCYPSESA，BIP4配体的序列为CRQTRTMPGC。这两个序列均来自环状噬菌体文库。与Bet v 1的序列比对未显示出相似性，表明这些抗体很可能识别不连续表位。展示这些模拟表位的噬菌体能够在ELISA中以剂量依赖的方式抑制抗Bet v 1单克隆抗体与Bet v 1的相互作用。相比之下，序列相同的合成肽在阻断抗体-过敏原相互作用方面无效。这与通过核磁共振光谱观察到的溶液中肽的构象不均匀性一致。在Balb/c小鼠中，胃内给予表达BIP1模拟表位的噬菌体可诱导Bet v 1特异性IgG反应。我们得出结论，当展示在噬菌体上时，肽模拟表位可能诱导保护性IgG反应，预防IgE介导的过敏反应，提示其可能具有临床应用价值。
