Lee M K, Kim K L, Hahm K S
Peptide Engineering Research Unit, Korea Research Institute of Bioscience and Biotechnology, Taejon, Korea.
Biochem Mol Biol Int. 1996 Dec;40(6):1077-85. doi: 10.1080/15216549600201713.
Previously we reported that the N-terminal sequence 120/123-129 of the preS2 region of the hepatitis B virus surface antigen plays an important role on peptide antigenicity against a monoclonal antibody H8 (H8 mAb) by affecting the B cell epitope conformation of a peptide existing within the sequence 130-145 (Lee et al., Biochem. Mol. Biol. Int., 34, 159-168, 1994). In this study, we try to map the H8 mAb binding site using a series of substituted peptides in the sequence 131-143 by competitive ELISA. Peptide antigenicities were greatly reduced when the residues 131 (L), 137 (R), 140 (Y), 141 (F) and 142 (P) were substituted. The residues 133 (D), 134 (P) and 136 (V) had a slight affect on the mAb binding, whereas the residues 135 (R) and 139 (L) had no effects on the mAb binding. In contrast to H8 mAb, however, three anti-HBsAg polyclonal antisera showed the lowest bindings to the peptide substituted at position 135. These results suggest that the epitope against H8 mAb is discontinuously conformational.
此前我们报道过，乙肝病毒表面抗原前S2区的N端序列120/123 - 129通过影响序列130 - 145内存在的一种肽的B细胞表位构象，在针对单克隆抗体H8（H8 mAb）的肽抗原性方面发挥重要作用（Lee等人，《生物化学与分子生物学国际杂志》，34卷，159 - 168页，1994年）。在本研究中，我们试图通过竞争性ELISA，利用一系列位于序列131 - 143中的取代肽来定位H8 mAb结合位点。当131位（L）、137位（R）、140位（Y）、141位（F）和142位（P）的残基被取代时，肽的抗原性大幅降低。133位（D）、134位（P）和136位（V）的残基对mAb结合有轻微影响，而135位（R）和139位（L）的残基对mAb结合无影响。然而，与H8 mAb不同的是，三种抗HBsAg多克隆抗血清与135位被取代的肽结合最少。这些结果表明，针对H8 mAb的表位是不连续构象。
