UCB, Slough, United Kingdom.
Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom.
PLoS Biol. 2020 Sep 4;18(9):e3000821. doi: 10.1371/journal.pbio.3000821. eCollection 2020 Sep.
As a novel alternative to established surface display or combinatorial chemistry approaches for the discovery of therapeutic peptides, we present a method for the isolation of small, cysteine-rich domains from bovine antibody ultralong complementarity-determining regions (CDRs). We show for the first time that isolated bovine antibody knob domains can function as autonomous entities by binding antigen outside the confines of the antibody scaffold. This yields antibody fragments so small as to be considered peptides, each stabilised by an intricate, bespoke arrangement of disulphide bonds. For drug discovery, cow immunisations harness the immune system to generate knob domains with affinities in the picomolar to low nanomolar range, orders of magnitude higher than unoptimized peptides from naïve library screening. Using this approach, knob domain peptides that tightly bound Complement component C5 were obtained, at scale, using conventional antibody discovery and peptide purification techniques.
作为一种新颖的替代方法，可用于发现治疗性肽的既定表面展示或组合化学方法，我们提出了一种从牛抗体超长互补决定区（CDR）中分离小的、富含半胱氨酸的结构域的方法。我们首次表明，分离的牛抗体 knob 结构域可以通过在抗体支架的限制之外结合抗原而作为自主实体发挥作用。这产生了小到被认为是肽的抗体片段，每个片段都由复杂的、定制的二硫键排列稳定。对于药物发现，牛免疫利用免疫系统产生具有皮摩尔至低纳摩尔范围亲和力的 knob 结构域，比未经优化的从原始文库筛选的肽高几个数量级。使用这种方法，使用传统的抗体发现和肽纯化技术，从大规模规模获得了紧密结合补体成分 C5 的 knob 结构域肽。
