Molecular farming: Expanding the field of edible vaccines for sustainable fish aquaculture

Abstract

Vaccines represent one of the most promising strategies for mitigating economic losses imposed by infectious diseases to global aquaculture. While the majority of commercial vaccines employ injection as the main route of delivery, a substantial body of research explores other avenues for the stimulation of protective immunity. Oral vaccines, representing the most favourable and convenient solution for the aquaculture industry, have been at the forefront of scientific interest for the last couple of decades. The orchestrated effort resulted in identifying the main roadblocks on the path to an ideal edible vaccine and provided several ingenious solutions improving the activation of immunity, ensuring the stability of administered antigens and their uptake upon the passage through the stomach. In the presented review, we describe advances in the available knowledge of the processes prerequisite for developing protective mucosal vaccines and focus readers' attention on the untapped potential of plant-based production systems in this effort. We propose that these approaches not only meet production demands but also fulfil all requirements of an oral vaccine, addressing all the obstacles, previously solved via separate strategies, in one platform. Thus, combined with the available knowledge of molecular adjuvants and produced for a fraction of the cost, plant-based production, so-called molecular farming, is an ideal candidate for vaccine development, paving the road to sustainable aquaculture.