[Expression of porcine interferon-gamma gene in Pichia pastoris and its effect of inhibiting porcine reproductive and respiratory syndrome virus].

In order to develop recombinant porcine Interferon-gamma (rPoIFN-gamma) to prevent porcine viral infection, PoIFN-gamma cDNA lacking the signal peptide was expressed in Pichia pastoris GS115 strain, and the effect of rPoIFN-gamma on porcine reproductive and respiratory syndrome virus (PRRSV) was investigated. The PoIFN-gamma gene was inserted into integrative vector pHIL-S1, and the recombinant GS115 strain (pHIL-S1/PoIFN-gamma) was constructed by homologues recombinant. The rPoIFN-gamma protein was 18 kD with an expressing yield of 18% was assayed by SDS-PAGE and Western blot, respectively. The anti-viral activity of rPoIFN-gamma was in the range of 450-540 u/mL. In addition, the effect of rPoIFN-gamma ant-PRRSV was determined using CPE50 method. The results indicated that high concentration of rPoIFN-gamma could inhibit PRRSV on Marc-145 cell line. The rPoIFN-gamma is a potential drug for prevention and treatment of various kinds of viral pig diseases.