PDF(Pubmed)
Abstract：
Enterotoxigenic Escherichia coli (ETEC) strains are significant contributors to postweaning diarrhea in piglets. Of the ETEC causing diarrhea, K88 and F18 accounted for 92.7%. Despite the prevalence of ETEC K88 and F18, there is currently no effective vaccine available due to the diversity of these strains. This study presents an innovative approach by isolating chicken-derived single-chain variable fragment antibodies (scFvs) specific to K88 and F18 fimbrial antigens from chickens immunized against these ETEC virulence factors. These scFvs effectively inhibited adhesion of K88 and F18 to porcine intestinal epithelial cells (IPEC-J2), with the inhibitory effect demonstrating a dose-dependent increase. Furthermore, a bispecific scFv was designed and expressed in Pichia pastoris. This engineered construct displayed remarkable potency; at a concentration of 25.08 μg, it significantly reduced the adhesion rate of ETEC strains to IPEC-J2 cells by 72.10% and 69.11% when challenged with either K88 or F18 alone. Even in the presence of both antigens, the adhesion rate was notably decreased by 57.92%. By targeting and impeding the initial adhesion step of ETEC pathogenesis, this antibody-based intervention holds promise as a potential alternative to antibiotics, thereby mitigating the risks associated with antibiotic resistance and residual drug contamination in livestock production. Overall, this study lays the groundwork for the development of innovative treatments against ETEC infections in piglets.
摘要：
产肠毒素大肠杆菌（ETEC）菌株是仔猪断奶后腹泻的重要原因。在导致腹泻的ETEC中，K88和F18占92.7%。尽管ETECK88和F18流行，但由于这些菌株的多样性，目前尚无有效的疫苗。这项研究通过从针对这些ETEC毒力因子免疫的鸡中分离对K88和F18菌毛抗原具有特异性的鸡衍生的单链可变片段抗体（scFvs），提出了一种创新方法。这些scFvs有效抑制K88和F18对猪肠道上皮细胞（IPEC-J2）的粘附，抑制作用表现出剂量依赖性增加。此外，设计双特异性scFv并在巴斯德毕赤酵母中表达。该工程构建体显示出显着的效力；浓度为25.08μg，单独用K88或F18攻击时，ETEC菌株对IPEC-J2细胞的粘附率显着降低了72.10％和69.11％。即使在这两种抗原的存在下，附着率显著下降57.92%。通过靶向和阻碍ETEC发病机制的初始粘附步骤，这种基于抗体的干预措施有望成为抗生素的潜在替代品，从而减轻与抗生素耐药性和牲畜生产中残留药物污染相关的风险。总的来说,这项研究为开发针对仔猪ETEC感染的创新治疗方法奠定了基础。
