Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, Cambridgeshire, UK.
Microb Cell Fact. 2021 Oct 2;20(1):193. doi: 10.1186/s12934-021-01682-4.
Poultry is the world's most popular animal-based food and global production has tripled in the past 20 years alone. Low-cost vaccines that can be combined to protect poultry against multiple infections are a current global imperative. Glycoconjugate vaccines, which consist of an immunogenic protein covalently coupled to glycan antigens of the targeted pathogen, have a proven track record in human vaccinology, but have yet to be used for livestock due to prohibitively high manufacturing costs. To overcome this, we use Protein Glycan Coupling Technology (PGCT), which enables the production of glycoconjugates in bacterial cells at considerably reduced costs, to generate a candidate glycan-based live vaccine intended to simultaneously protect against Campylobacter jejuni, avian pathogenic Escherichia coli (APEC) and Clostridium perfringens. Campylobacter is the most common cause of food poisoning, whereas colibacillosis and necrotic enteritis are widespread and devastating infectious diseases in poultry.
We demonstrate the functional transfer of C. jejuni protein glycosylation (pgl) locus into the genome of APEC χ7122 serotype O78:H9. The integration caused mild attenuation of the χ7122 strain following oral inoculation of chickens without impairing its ability to colonise the respiratory tract. We exploit the χ7122 pgl integrant as bacterial vectors delivering a glycoprotein decorated with the C. jejuni heptasaccharide glycan antigen. To this end we engineered χ7122 pgl to express glycosylated NetB toxoid from C. perfringens and tested its ability to reduce caecal colonisation of chickens by C. jejuni and protect against intra-air sac challenge with the homologous APEC strain.
We generated a candidate glycan-based multivalent live vaccine with the potential to induce protection against key avian and zoonotic pathogens (C. jejuni, APEC, C. perfringens). The live vaccine failed to significantly reduce Campylobacter colonisation under the conditions tested but was protective against homologous APEC challenge. Nevertheless, we present a strategy towards the production of low-cost "live-attenuated multivalent vaccine factories" with the ability to express glycoconjugates in poultry.
家禽是全球最受欢迎的动物源性食品，仅在过去 20 年里，其全球产量就增长了两倍。能够低成本制备、可同时针对多种感染进行保护的疫苗是目前全球的迫切需求。糖缀合物疫苗由免疫原性蛋白与目标病原体的聚糖抗原通过共价键连接而成，在人类疫苗学中已有成熟的应用，但由于生产成本过高，尚未用于家畜。为了克服这一难题，我们使用蛋白聚糖偶联技术（PGCT），可在细菌细胞中以显著降低的成本生产糖缀合物，从而生成一种候选糖基活疫苗，旨在同时预防空肠弯曲菌、禽致病性大肠杆菌（APEC）和产气荚膜梭菌。空肠弯曲菌是食物中毒最常见的原因，而大肠杆菌病和坏死性肠炎是家禽中广泛存在且具有毁灭性的传染性疾病。
我们证明了空肠弯曲菌蛋白糖基化（pgl）基因座可功能性转移至 APEC χ7122 血清型 O78:H9 的基因组中。该整合使 χ7122 菌株在鸡口服接种后出现轻度衰减，而不影响其在呼吸道定植的能力。我们利用 χ7122 pgl 整合子作为细菌载体，表达用空肠弯曲菌七糖聚糖抗原修饰的糖蛋白。为此，我们设计 χ7122 pgl 表达产气荚膜梭菌 NetB 类毒素的糖基化形式，并测试其降低鸡空肠弯曲菌定植的能力和对同源 APEC 菌株气囊内攻毒的保护作用。
我们生成了一种候选糖基多价活疫苗，具有诱导针对关键禽源和人畜共患病病原体（空肠弯曲菌、APEC、产气荚膜梭菌）保护的潜力。活疫苗在测试条件下未能显著降低空肠弯曲菌定植，但对同源 APEC 攻毒具有保护作用。然而，我们提出了一种生产低成本“活减毒多价疫苗工厂”的策略，该策略可使家禽表达糖缀合物。
