Expression of Sheep Interferon Gamma in Silkworm Baculovirus System and Antiviral Activity Assay of Expressed Product

Shao Liping;Lü Yanna;Yang Xin;Zhao Ze;Hu Xiaoyuan;Li Yinü;Zhang Zhifang;Yi Yongzhu;College of Biotechnology,Jiangsu University of Science and Technology;Biotechnology Research Institute,Chinese Academy of Agricultural Sciences;

College of Biotechnology,Jiangsu University of Science and Technology%Biotechnology Research Institute,Chinese Academy of Agricultural Sciences

Sheep interferon gamma;;Silkworm baculovirus expression system;;Silkworm larva;;Recombinant protein;;Antiviral activity

Interferon( IFN) has a broad spectrum of antiviral activity. In order to meet the requirement of using interferon in prevention and treatment of livestock virus disease,the feasibility of preparing recombinant sheep interferon( Ovi IFN-γ) by silkworm baculovirus expression system is explored. The Ovi IFN-γ gene sequence was optimized according to codon bias of silkworm and amplified through PCR. The Ovi IFN-γ gene sequence with His tag sequence( Ovi IFN-HisTagged-γ) was cloned and used to construct recombinant viruses containing Ovi IFN-γ and Ovi IFN-His-Tagged-γ respectively. These two recombinant viruses were used to infect silkworm larvae of the 5th instar. Western blotting revealed successful expression of recombinant Ovi IFN-γ and Ovi IFN-His-Tagged-γ in hemolymph of silkworm. The recombinant Ovi IFN-γ in silkworm hemolymph had a titer of 1. 6×106U/m L and that of recombinant Ovi IFN-His-Tagged-γ had a titer of was 2. 8× 105U/m L as detected by cytopathic inhibition method. The former had a stronger antiviral activity than thelatter. When diluted by 2. 0×104times,it could completely inhibit VSV-GFP virus infection. The above results provide a good experimental basis for efficient and safe production of recombinant interferon γ with antiviral activity in silkworm baculovirus expression system.