Development of a mucosally-delivered and active salmon louse vaccine for Atlantic salmon aquaculture

鲑鱼虱是一种体表寄生虫，以鲑鱼的粘液、皮肤、底层组织和血液为食，对养殖的大西洋鲑鱼来说是一个特别的问题。鲑鱼虱子对全球大西洋鲑鱼产业的经济影响估计为每年10亿美元。大西洋鲑鱼水产养殖业是英国经济的关键贡献者，每年价值超过10亿英镑。苏格兰政府打算在2016至2030年间将大西洋鲑鱼产量翻一番。然而，鲑鱼虱子是制约该行业扩张的最大因素。该行业使用各种方法来控制鲑鱼虱子的侵扰，包括化疗药物、热或水力消毒剂、浮潜网箱和更清洁的鱼。然而，这些方法的应用和有效性存在重大挑战，鲑鱼养殖业继续寻找新的环境友好型解决方案来控制鲑鱼虱子感染，这些方法比目前使用的方法提供更好的鱼类福利、更少的处理、更少的压力和更少的身体创伤。商业鲑鱼虱子疫苗将提供一种实用、安全和环保的方法来管理鲑鱼虱子，并加强目前用于控制鲑鱼虱子的策略。目前还没有针对沙门氏菌的商业疫苗；开发一种针对这种寄生虫的有效疫苗一直是具有挑战性的。通过腹腔注射注射鲑鱼虱子疫苗的传统方法显示出有限的成功，主要是因为它们无法在虱子滋养的部位--即皮肤的粘膜表面--引发适当的免疫反应。该项目的重点是开发一种有效的原型疫苗，通过刺激大西洋鲑鱼皮肤内的保护性粘膜免疫反应来保护大西洋鲑鱼免受鲑鱼虱子的侵袭。我们的目标是创造一种可以口服给鱼的疫苗，以增强系统和粘膜免疫反应，从而增加针对海虱产生有效粘膜免疫保护的机会。合适的疫苗目标是那些影响寄生虫生物学的生物，如附着、发育和/或成熟，并存在于寄生虫生命周期的寄生阶段。我们的创新方法将使用反向疫苗学(RV)来快速确定鲑鱼虱内的关键生物靶点，以开发新的疫苗。这涉及到使用生物信息学工具从鲑鱼虱子的基因组中识别硅胶中的抗原。我们将把它与人工智能(AI)抗原预测平台(EPitopePredikt)相结合，以协助抗原发现和对接潜力，准确定位可被鱼类免疫球蛋白(IgM和IGT抗体)识别的免疫原表位。这将允许有针对性地选择候选疫苗进行体内评估。这些将被整合到一种独特的黏膜抗原呈递支架中，用于口服递送。多种抗原将使用表位/肽表达平台(EbitoGen)在单一支架上表达，因此在免疫/感染试验中进行抗原评估所需的鱼类较少，鱼类的免疫反应暴露于支架上的几个重组表位，以产生更强大的免疫反应。我们疫苗的效力将通过它减少实验感染鲑鱼虱子的接种鱼身上虱子数量(和/或雌性鲑鱼虱子的繁殖力)的能力来衡量。该项目是莫雷登研究所(MRI)、斯特林大学水产养殖研究所(IOA)、Bimeda动物健康(BAH)和脊椎动物抗体有限公司(Val)之间的跨学科合作，由BAH提供工业奖合作伙伴关系。

The salmon louse, Lepeophtheirus salmonis, is an ectoparasite that feeds on the mucus, skin, underlying tissues, and blood of salmonid fish and is a particular issue for farmed Atlantic salmon. The economic impact of salmon lice on the global Atlantic salmon industry is estimated to be $1 US billion annually. The Atlantic salmon aquaculture industry is a key contributor to the UK economy, worth over £1 billion annually. The Scottish Government intends to double the value of Atlantic salmon production between 2016 and 2030. However, salmon lice are the biggest constraint to the expansion of the industry. The industry uses various methods to control salmon lice infestations, including chemotherapeutants, thermo or hydro-licers, snorkel cages and cleaner fish. However, there are major challenges with the application and efficacy of these approaches, and the salmon farming industry continues to look for new environmentally friendly solutions to control salmon lice infections, which offer better fish welfare, less handling, less stress, and less physical trauma than the methods currently employed. A commercial salmon louse vaccine would provide a practical, safe, and eco-friendly approach to managing salmon lice and enhance the current strategies used to control salmon lice. No commercial vaccines are available for L. salmonis; developing an efficacious vaccine against this parasite has been challenging. Traditional methods for administering salmon lice vaccines by intraperitoneal injection have shown limited success, primarily due to their inability to elicit a suitable immune response at the site where the lice feed - i.e., the mucosal surface of the skin. This project focuses on developing an effective prototype vaccine to protect Atlantic salmon from salmon lice by stimulating a protective mucosal immune response within their skin. We aim to create a vaccine that can be orally administered to fish to enhance both systemic and mucosal immune responses, thus increasing the chances of generating effective mucosal immune protection against sea lice. Appropriate vaccine targets are those that affect parasite biology, such as attachment, development and/or maturation and which are present during parasitic stages of the louse's life cycle. Our innovative approach will use reverse vaccinology (RV) to quickly identify key biological targets within the salmon louse for novel vaccine development. This involves identifying antigens in silico from the genome of the salmon louse using bioinformatic tools. We will integrate this with an artificial intelligence (AI) antigen prediction platform (EpitopePredikt) to assist in antigen discovery and docking potential, pinpointing immunogenic epitopes that can be recognised by fish immunoglobulins (IgM and IgT antibodies). This will allow a targeted selection of vaccine candidates for assessment in vivo. These will be integrated into a unique mucosal antigen-presenting scaffold for oral delivery. Multiple antigens will be expressed on a single scaffold using an epitope/peptide expression platform (EpitoGen), so fewer fish are needed for antigen assessment in immunisation/infection trials, and the immune response of fish is exposed to several recombinant epitopes on the scaffold to produce a more robust immune response. The efficacy of our vaccine will be measured by its ability to reduce the number of lice (and/or the fecundity of female salmon lice) on vaccinated fish that have been experimentally infected with salmon lice. This project is an interdisciplinary collaboration between the Moredun Research Institute (MRI), the University of Stirling's Institute of Aquaculture (IoA), Bimeda Animal Health (BAH), and Vertebrate Antibodies Ltd (VAL) with an Industrial Award Partnership contribution from BAH.