The development of inhibitors for the infection using phage library

已知流感HA在感染的第一步与宿主细胞结合具有α2-3-或α2-6-键的唾液酰半乳糖苷。我们试图设计多肽作为一种通用抑制剂，结合到HA的受体结合口袋。为了获得模拟唾液寡糖的肽，采用了噬菌体显示随机五肽文库。噬菌体展示法是一种利用噬菌体池进行筛选的技术。预计从噬菌体文库中选择的ha结合肽将作为甲型流感病毒的抑制剂。本研究从噬菌体展示的肽库中选择ha结合肽和糖脂结合肽，它们抑制了流感病毒HA1和HA3亚型对MDCK细胞的感染。虽然理论上计算的五肽分子多样性为3.3x10^<19>，但所采用的噬菌体文库只有2.5x10^8种多样性。因此，为了获得改进的ha结合肽，我们从选定的序列中生成亚库。采用定向进化方法制备子库。构建这两种亚库分别获得HA1-和ha3结合肽。利用亚库对HA1和HA3进行亲和选择，获得了多个突变肽序列。许多突变噬菌体克隆对HA1和HA3亚型的结合亲和力高于原始的A-1噬菌体。进化的肽比原A-1肽更有效地抑制流感病毒对MDCK细胞的感染。

Influenza HA is known to bind sialylgalactoside having α2-3- or α2-6- linkages on host cells at the first step of infection. We attempted to design peptides as a universal inhibitor that bind to the receptor-binding pocket of HA.In order to obtain peptides which are a mimic of sialyl oligosaccharide, a phage-displayed random pentadecapeptide library have been employed. phage-displayed method is a selection technology using a pool of phage. It was expected that HA-binding peptides selected from the phage library would serve as inhibitors of influenza A virus. In this study, the HA-binding peptides and glycolipid-binding peptides were selected from the phage-displayed peptide libraries, and they inhibited the infection of both HA1 and HA3 subtypes of influenza virus to MDCK cells. Although the theoretical molecular diversity of pentadecapeptide is calculated to be 3.3x10^<19>, the phage library employed has only 2.5x10^8 kinds of diversity. Therefore, in order to obtain improved the HA-binding peptides, sublibrary generated from a selected sequence was prepared. The directed evolution approach was employed to prepare the sublibraries.The two kinds of sublibraries were constructed to obtain HA1- and HA3-binding peptides. Through the affinity selections for HA1 and HA3 using the sublibraries, several peptide sequences having mutations were obtained. Many of the mutant phage clones showed higher binding affinity for both HA1 and HA3 subtypes than the original A-1 phage. The evoluted peptides inhibited the infection of influenza virus to MDCK cells more efficiently than the original A-1 peptide.