Construction of recombinant Lactococcus expressing thymosin and interferon fusion protein and its application as an immune adjuvant

Abstract

Abstract In this study, recombinant food-grade Lactococcus lactis (r-L. lactis-Tα1-IFN) expressing thymosin Tα1 and interferon fusion protein was constructed. In vitro interaction with macrophages showed that recombinant r-L. lactis-Tα1-IFN could significantly activate both macrophage J774-Dual™ NF-κB signaling pathway and IRF signaling pathway. In vitro interaction with chicken, PBMCs showed that recombinant r-L. lactis-Tα1-IFN significantly enhanced the expression levels of IFN-γ, IL-10, CD80, and CD86 molecules in chicken PBMCs cells. Animal experiments showed that injection of recombinant r-L. lactis-Tα1-IFN could significantly activate the proliferation activity of T cells and antigen-presenting cells in chicken PBMCs, and the results of 16S analysis of intestinal microbiota showed that injection of recombinant r-L. lactis-Tα1-IFN could significantly improve the structure and composition of chicken intestinal microbiota, with a significant increase in probiotic genera such as Lactobacillus spp. were significantly increased. The results of animal experiments using recombinant r-L. lactis-Tα1-IFN as an immune adjuvant for inactivated chicken Newcastle disease vaccine showed that the serum HI antibody titers of the experimental group were extremely significantly higher than those of the vaccine control group, and the expression levels of cytokines IFN-γ, IL-2, and IL-10 were significantly higher than those of the vaccine control group, These results indicate that food-safe recombinant r-L. lactis-Tα1-IFN has potential as a vaccine immune booster and immune adjuvant, and this study lays the foundation for the development of natural green novel animal immune booster or immune adjuvant.