Novel biotherapeutics for the prevention and control of Campylobacter spp. in chickens

就发病率和造成的损害而言，最重要的食物中毒细菌是弯曲杆菌。在英国，每年估计有100万例食源性疾病病例，弯曲杆菌导致多达75万例病例，2.2万例住院治疗和110例死亡。食品标准局目前的估计表明，在英国，人类弯曲杆菌病的成本约为10亿英镑，而所有食源性感染的总成本约为15亿英镑。弯曲杆菌存在于供人类食用的动物胃肠道中，肉类加工过程中的粪便污染是公认的传播给人类的途径。在英国销售的生鸡肉中，高达80%被弯曲杆菌污染，研究表明，在所有报告的地方性感染中，有50-70%是由食用家禽引起的。目前在英国销售的生家禽的污染水平造成了令人无法接受的高公共卫生负担，人类弯曲杆菌病病例的数量继续增加。需要其他策略来减少鸡中的弯曲杆菌和人类的相关疾病负担。一旦鸡被弯曲杆菌定植，就会产生针对该细菌的抗体，并且观察到在肠道定植的弯曲杆菌数量减少。这些数据表明，使用抗弯曲杆菌抗体的被动免疫疗法可能是一种干扰鸡定植的方法。这种方法也可以使人类和其他动物受益。有证据支持这一点，即在一般人群中，大多数人在感染后对许多弯曲杆菌抗原产生体液免疫反应，流行病学研究表明，这种免疫对于预防弯曲杆菌疾病的发展至关重要。抗体片段或类似的小肽分子很少被用作治疗药物。我们认为，它们具有潜在的治疗和预防治疗鸡，人类和其他动物对弯曲杆菌。我们建议使用抗体文库技术、蛋白质定向筛选和早期功能筛选来鉴定阻断或损害弯曲杆菌蛋白活性的单链Fvs （scFvs）。我们计划通过一种无害的益生菌——枯草芽孢杆菌（Bacillus subtilis）——以营养细胞或孢子的形式传递这些分子，这种细菌经过基因改造，可以在鸡胃肠道内原位合成或释放抗体片段，从而为体内治疗和预防应用提供持续的scFv来源。这种就地生产scFv的方法比通过传统方法输送相同的试剂有许多优点。例如，取消下游加工步骤，降低货物成本，并取消对复杂的剂量方案或运输工具的任何要求。这种治疗方法可以通过食物或饮料来提供。或者，细菌和/或细菌孢子可以用来生产scFv(s)廉价和容易用于更传统的药物输送方法。

The most important food-poisoning bacterium both in terms of incidence and in the damage that it causes is Campylobacter. In the UK, out of an estimated one million cases of foodborne disease each year, Campylobacter is responsible for up to 750,000 cases, 22,000 hospitalisations and 110 deaths. Current estimates by the Food Standards Agency indicate that the cost of human campylobacteriosis in the UK is around £1B, out of a total of around £1.5B for all foodborne infections. Campylobacter is found in the gastrointestinal tracts of animals destined for human consumption, with faecal contamination of meat during processing a recognised route of transmission to humans. Up to 80% of raw chicken sold in the UK is contaminated with Campylobacter, and studies suggest that the consumption of poultry is responsible for 50-70% of all endemic infections that are reported. The current level of contamination of raw poultry on sale in the UK presents an unacceptably high public health burden, and the number of human campylobacteriosis cases continues to increase. Alternative strategies are needed to reduce Campylobacter in chickens and the associated disease burden in humans.Once a chicken is colonised with Campylobacter, antibodies against the bacterium are generated and a decrease in the number of Campylobacter colonising the intestinal tract has been observed. These data suggest that passive immunotherapy using anti-Campylobacter antibodies could be an approach for interfering with colonisation in chickens. The approach could also benefit humans and other animals. This is supported by the evidence that, in the general population, humoral immune response to a number of Campylobacter antigens is developed in most people upon infection, and epidemiological studies indicate that the immunity is crucial for the development of protection against Campylobacter disease.Antibody fragments or similar small peptide molecules are under-used as therapeutics. We contend that they have potential as therapeutic and prophylactic treatments for chickens, humans and other animals against Campylobacter. We propose to use antibody library technologies, protein-directed panning and early engagement of functional screens to identify single-chain Fvs (scFvs) that block or impair the activity of Campylobacter proteins. We plan to deliver the molecules via a harmless probiotic bacterium, Bacillus subtilis, either in vegetative cell or spore form, that has been genetically altered to synthesise or release the antibody fragment in situ within the chicken gastrointestinal tract, thus providing a continuous source of scFv in vivo for therapeutic and prophylactic applications. This local in situ production of scFv has many advantages over delivery of the same reagent by conventional means. For example, removing downstream processing steps, reducing the cost of goods, and doing away with any requirement for complex dosing regimens or delivery vehicles. Such a therapeutic could be delivered in food or drink. Alternatively, the bacteria and/or bacterial spores could be used to produce the scFv(s) cheaply and easily for more traditional methods of drug delivery.