Plant production and functional characterization of catfish interleukin-22 as a natural immune stimulant for aquaculture fish

As the world population increases and wild caught fisheries decline, aquaculture offers a sustainable solution addressing this global challenge. However, disease management remains difficult. With limited options, there is a need for innovative solutions. The cytokine interleukin-22 (IL-22) has emerged as a possible therapeutic target for fish and has been correlated with protection under pathogen challenge. Plant-based production systems have the potential to effectively manufacture and bring unique efficacy-enhancing features to the aquaculture industry; namely, the advantages of low cost for this commodity market, ready scalability, and reduced environmental impact. Catfish IL-22 produced at significant yield and purity highlights the use of plants as a promising production platform for therapeutic proteins with utility to the aquaculture industry. Purified cfIL-22 shows similar in vitro bioactivity to its mammalian homolog that include increased proliferation of catfish cells highlighting the tissue preservation capabilities associated with this protein. Recombinant cfIL-22 also upregulated expression of genes encoding a tissue repair protein, fibronectin, an antimicrobial peptide, Natural killer lysin-1, and a common innate immune protein, interferon. These findings support plant-made recombinant catfish interleukin-22 as a potential therapeutic for the aquaculture industry and further analysis of this protein for promoting animal health.