A yeast surface display method tailored for nanobody display

家禽业是加拿大经济的重要组成部分，2011年对加拿大GDP的贡献超过65亿美元，出口额约为3.5亿美元。感染家禽的人畜共患细菌对人类消费构成严重挑战，特别是现在人畜共患病原体对传统抗生素的耐药性越来越强。AbCelex是一家加拿大公司，开发单域抗体，也被称为纳米体，用于对抗人畜共患细菌。AbCelex纳米体防止病原体在家禽肠道定植，使动物更健康，同时减少供人类食用的禽肉的细菌污染。纳米体商业化的一个主要障碍是与生产和纯化过程相关的高成本。AbCelex目前正在使用一种在酵母表面表达纳米体的策略，这种策略消除了关键的纯化步骤，有可能克服市场上的一个主要障碍。然而，现有的纳米体酵母表面显示方法还远远不够理想，因为它们只能在约20%的细胞中实现表面表达，降低了效率，从而增加了成本。AbCelex与多伦多大学Sergio Peisajovich教授的实验室合作，旨在设计一种为纳米体量身定制的新型酵母表面显示方法，将表面显示水平提高到至少80%的细胞，从而消除商业化的主要障碍。为了实现这一目标，我们将系统地筛选所有合适的酵母gpi锚定细胞壁蛋白，以确定最佳的融合伙伴，在细胞表面展示纳米体。AbCelex纳米体基饲料添加剂用于预防家禽细菌污染可能为解决家禽业的主要问题之一提供急需的补救措施。该提案将大大有助于消除AbCelex纳米体商业化的主要障碍，从而使加拿大经济中的一个重要参与者受益，同时有助于减少加拿大和世界各地的食源性疾病。

The poultry industry is a major player in Canada's economy, contributing more than ~$6.5B to Canada's GDP in 2011, with ~$350M in exports. Zoonotic bacteria infected poultry poses a serious challenge to human consumption, particularly now that zoonotic pathogens are becoming increasingly resistant to traditional antibiotics. AbCelex is a Canadian company developing single-domain antibodies, also known as nanobodies, against zoonotic bacteria. AbCelex nanobodies prevent pathogen colonization of poultry gut, resulting in healthier animals while reducing bacterial contamination of poultry meat for human consumption. A major barrier to nanobodies commercialization is the high cost associated with the production and purification processes. AbCelex is currently using a strategy for expression of nanobodies on the yeast surface that eliminates key purification steps, potentially overcoming a major barrier to market. However, existing methods for nanobody yeast surface display are far from ideal, as they result on surface expression only in ~20% of the cells, reducing efficiency and thus increasing cost. The collaboration between AbCelex and the laboratory of Prof. Sergio Peisajovich, at the University of Toronto, is aimed at engineering a novel yeast surface display method tailored for nanobodies to increase surface display levels to at least 80% of the cells, thus eliminating a major barrier to commercialization. Towards this goal, we will systematically screen all suitable yeast GPI-anchored cell wall proteins to identify optimal fusion partners to display nanobodies on the cell surface. AbCelex nanobody-based feed additive for prevention of bacterial contamination in poultry could provide a much-needed remedy to one of the poultry industry major problems. This proposal will substantially contribute to eliminate a major barrier to AbCelex nanobody commercialization, thus benefiting an important player in Canada's economy, while contributing to reduce foodborne diseases in Canada and around the world.