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

鲑鱼虱（Lepeophtheirus salmonis）是一种外寄生虫，以鲑鱼的粘液、皮肤、底层组织和血液为食，是养殖大西洋鲑鱼的一个特殊问题。鲑鱼虱对全球大西洋鲑鱼产业的经济影响估计每年为10亿美元。大西洋鲑鱼养殖业是英国经济的主要贡献者，每年价值超过10亿英镑。苏格兰政府计划在2016年至2030年期间将大西洋鲑鱼产量翻一番。然而，鲑鱼虱是该行业扩张的最大制约因素。该行业使用各种方法来控制鲑鱼虱感染，包括化疗剂，热或水licers，通气管笼和清洁鱼。然而，这些方法的应用和功效存在重大挑战，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感染，与目前采用的方法相比，这些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。商业鲑鱼虱疫苗将提供一种实用，安全和生态友好的方法来管理鲑鱼虱，并加强目前用于控制鲑鱼虱的策略。目前尚无L.沙门氏菌;开发针对这种寄生虫的有效疫苗一直具有挑战性。通过腹膜内注射施用鲑鱼虱疫苗的传统方法已经显示出有限的成功，主要是由于它们不能在虱进食的部位（即，皮肤的粘膜表面。该项目的重点是开发一种有效的原型疫苗，通过刺激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的侵害。我们的目标是创造一种疫苗，可以口服给药的鱼，以增强全身和粘膜免疫反应，从而增加产生有效的粘膜免疫保护对海虱的机会。适当的疫苗靶标是影响寄生虫生物学的那些，例如附着、发育和/或成熟，并且存在于虱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）来快速识别鲑鱼虱中的关键生物靶点，以开发新型疫苗。这涉及使用生物信息学工具从鲑鱼虱的基因组中通过计算机识别抗原。我们将其与人工智能（AI）抗原预测平台（EpitopePredikt）相结合，以协助抗原发现和对接潜力，精确定位可被鱼类免疫球蛋白（IgM和IgT抗体）识别的免疫原性表位。这将允许有针对性地选择用于体内评估的候选疫苗。这些将被整合到一个独特的粘膜抗原呈递支架用于口服递送。使用表位/肽表达平台（EpitoGen），多种抗原将在单个支架上表达，因此在免疫/感染试验中需要更少的鱼进行抗原评估，并且鱼的免疫应答暴露于支架上的几个重组表位，以产生更稳健的免疫应答。我们的疫苗的效力将通过其减少实验感染鲑鱼虱的接种鱼上的虱数量（和/或雌性鲑鱼虱的繁殖力）的能力来衡量。该项目是Moredun研究所（MRI），斯特林大学水生生物研究所（IoA），Bimeda动物健康（BAH）和脊椎动物抗体有限公司（瓦尔）之间的跨学科合作，BAH提供了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.