Radhakrishnan Akshaya, Vaseeharan Baskaralingam, Ramasamy Pasiyappazham, Jeyachandran Sivakamavalli
Department of Biotechnology and Microbiology, National College (Autonomous), Tiruchirappalli, Tamil Nadu 620001 India.
Department of Animal Health & Management, Alagappa University, Karaikudi, Tamil Nadu 630003 India.
Aquac Int. 2023;31(2):867-891. doi: 10.1007/s10499-022-01004-4. Epub 2022 Nov 14.
The prevalence of infectious diseases in the aquaculture industry and a limited number of safe and effective oral vaccines has imposed a challenge not only for fish immunity but also a threat to human health. The availability of fish oral vaccines has expanded recently, but little is known about how well they work and how they affect the immune system. The unsatisfactory efficacy of existing oral vaccinations is partly attributable to the antigen degradation in the adverse gastrointestinal environment of fishes, the highly tolerogenic gut environment, and inferior vaccine formulation. To overcome such challenges in designing: an easier, cost-efficient, and effective vaccination method, several encapsulation methods are being adopted to safeguard antigens from the intestinal atmosphere for their immunogenic functions. Oral vaccination is easily degraded by gastric acids and enzymes before reaching the immunological site; however, this issue can be solved by encapsulating antigens in poly-biodegradable nanoparticles, transgenic designed bacteria, plant systems, and live feeds. To enhance the immunological impact, each antigen delivery method operates at a different level. Utilizing nanotechnology, it has been possible to regulate vaccination parameters, target particular cells, and lower the antigen dosage with potent nanomaterials such as chitosan, poly D,L-lactic-co-glycolic acid (PLGA) as vaccine carriers. Live feeds such as can be utilized as bio-carrier, owing to their appropriate size and non-filter feed system, through a process called bio-encapsulation. It ensures the protection of antigens over the fish intestine and ensures complete uptake by immune cells in the hindgut for increased immune response. This review comprises recent advances in oral vaccination in aquaculture in terms of an encapsulation approach that can aid in future research.
水产养殖业中传染病的流行以及安全有效的口服疫苗数量有限，不仅对鱼类免疫构成挑战，也对人类健康构成威胁。鱼类口服疫苗的种类最近有所增加，但对于它们的作用效果以及如何影响免疫系统却知之甚少。现有口服疫苗效果不尽人意，部分原因在于鱼类不利的胃肠道环境中抗原会降解、肠道环境具有高度耐受性以及疫苗配方不佳。为了在设计更简便、经济高效且有效的疫苗接种方法时克服这些挑战，人们采用了几种包封方法来保护抗原免受肠道环境影响，以发挥其免疫功能。口服疫苗在到达免疫部位之前很容易被胃酸和酶降解；然而，通过将抗原包封在可生物降解的纳米颗粒、转基因设计细菌、植物系统和活饲料中，可以解决这个问题。为了增强免疫效果，每种抗原递送方法在不同层面发挥作用。利用纳米技术，可以通过壳聚糖、聚D,L-乳酸-乙醇酸共聚物（PLGA）等有效的纳米材料作为疫苗载体来调节疫苗接种参数、靶向特定细胞并降低抗原剂量。像卤虫无节幼体这样的活饲料由于其合适的大小和非滤食性摄食系统，可以通过一种称为生物包封的过程用作生物载体。这确保了抗原在鱼肠道内得到保护，并确保后肠中的免疫细胞能够完全摄取，从而增强免疫反应。本综述涵盖了水产养殖口服疫苗接种方面的最新进展，涉及有助于未来研究的包封方法。
