Expressions of Bovine IFN-γ and Foot-and-Mouth Disease VP1 antigen in P. pastoris and their effects on mouse immune response to FMD antigens

As a highly contagious disease in cloven-hoofed animals, foot-and-mouth disease virus (FMDV) may cause a considerable social-economic loss in those countries affected. IFN-γ has a wide range of antiviral and immune modulating functions. Thus, to study the immune enhancing effects of recombinant Bovine IFN-γ (rBoIFN-γ) on a recombinant FMDV vaccine, BoIFN-γ, FMDV VP1 and BoIFN-γ/VP fusion genes were cloned, expressed, co-expressed in pichia pastoris (P. pastoris) respectively, and subsequent immune effects have been evaluated in this study. The results showed that the genes encoding for BoIFN-γ, VP1 and BoIFN-γ/VP1 are successfully expressed in P. pastoris and their products are directly secreted into the cultural supernatant at a high level of 1.0 g/L analyzed by thin-layer scanning. In addition, rVP1 alone could induce both humoral and marginal cell-mediated immune responses in mice, while the group with co-inoculations of rBoIFN-γ could markedly enhance both humoral and cell-mediated immune responses; even more dramatic immune responses were observed with the group inoculated with the fusion product, rBoIFN-γ/VP1. The fusion product could be further investigated for its utility of FMDV vaccine development.