Mucosal Vaccines in Fish: Novel Advances in Technology and Delivery: A Review

Abstract

Vaccines rely on the acquired immune system and prime an animal to a particular antigen so that on subsequent encounter; it is recognized and quickly destroyed. The vast majority of pathogens enter the body via the mucosal surfaces of the gastrointestinal, respiratory, and urogenital tracts, where they initiate mucosal infections that lead to systemic infections. There is strong evidence that an optimum mucosal immune response can prevent systemic infection and mucosal vaccines are also available considering their low efficiency. Most of the recently used immunization techniques in fish are ineffective to induce immunization at a mucosal surface. Among the novel vaccination methods, mucosal vaccination seems to possess all the desired criteria because mucosal organs are principle portals of entry for microbial invasion and as such developing protective vaccines against these pathogens can serve as the first line of defense against infections. Mucus serves as an important component of the innate immune mechanism in two ways.  Firstly, by-produced continuously and being sloughed off regularly, it prevents the adherence of pathogens and stable colonization of potentially infectious microbes and invasion of metazoan parasites. Secondly, it contains a number of factors of innate immunity like proteins and enzymes such as lysozyme, immunoglobulin, complement proteins, lectins, C-reactive protein (CRP), proteolytic enzymes, transferring, alkaline phosphatase (ALP) and various other antibacterial proteins and peptides, etc. neutralize invading pathogens on mucosal surfaces. This review focuses on the function of mucosal tissues and its role in innate and adaptive immune responses that result in immune protection at mucosal surfaces of fish. In this review, we have also discussed this type of vaccination with a focus on their uptake, immune stimulation, and their potential as future vaccines. It also discusses the information on the mucosal immune system, suitable mucosal antigens and adjuvants, and uptake mechanisms, etc. The chapter also summarizes a variety of methods that are employed to deliver antigen safely to the hindgut, induce local or systemic immune responses, and, most importantly, induce immunological memory and achieve long-term protection.

Keywords: Mucosal vaccine, Fish immune system, Route of vaccination and delivery system

Cite this Article

Supriya Dash, Jayshree Nanda, Shyamalini Shyamasuta, Anupama Baral, Aurobido Das. Mucosal Vaccines in Fish: Novel Advances in Technology and Delivery: A Review. Research & Reviews: A Journal of Immunology. 2019; 9(1): 14–26p.