Type II grass carp reovirus VP4-NS38 fusion protein gene, expression vector, strain and application thereof

Abstract

The invention discloses a type II grass carp reovirus VP4-NS38 fusion protein gene, an expression vector, a strain and application thereof. Proteins VP4 and NS38 capable of causing grass carp to generate immune response reactions of different modes are connected by a flexible linker through a fused PCR manner, so as to construct a recombinant bacillus capable of achieving fused expression of a protein GCRVVP4-NS38 in a gemma of bacillus subtilis. Through immunizing the grass carp with the recombinant bacillus in an oral administration manner, a grass carp body can be stimulated to generate a mucosa antibody with neutralizing activity and a serum antibody, the grass carp can be caused to generate a humoral immunization reaction, and the grass carp can also be caused to generate a cell immunization reaction; and meanwhile, inflammatory reactions of the grass carp during viral infection can also be reduced. The type II grass carp reovirus VP4-NS38 fusion protein gene, the expression vector and the strain have very good safety, do not generate remarkable influence on growth of the grass carp, will not cause pathologic lesion to tissue and organs of the grass carp and can be applied to researches on oral-administration vaccines for hemorrhage diseases of the grass carp.

Description

technical field [0001] The invention belongs to the field of genetic engineering, and in particular relates to type II grass carp reovirus VP4-NS38 fusion protein gene, carrier, bacterial strain and application thereof. Background technique [0002] Grass carp is the most important freshwater farmed fish in my country. According to statistics, the output of farmed grass carp in my country reached 5.3456 million tons in 2017. However, grass carp hemorrhagic disease caused by grass carp reovirus (GCRV) can cause diseased grass carp Congestion and hemorrhage symptoms of various organs and tissues in different degrees can lead to the death of the fish in severe cases, and the fatality rate is as high as 85%. At present, grass carp hemorrhagic disease is widely prevalent in my country's Hubei, Hunan, Guangdong, Guangxi, Jiangsu, Zhejiang, Anhui, Fujian, Shanghai, Sichuan and other grass carp main breeding areas. huge economic losses. At present, there is no specific and effective...

AI Technical Summary

Problems solved by technology

[0007] However, compared with traditional injection immunization, the immune protection rate of bacillus oral vaccine is low, which limits its application effect

Oral immunization of grass carp with recombinant Bacillus expressing GCRV VP4 protein using Bacillus subtilis as a carrier can effectively stimulate fish to produce immune protection, but compared with traditional attenuated vaccine injection immunization, the immune protection rate of recombinant Bacillus GCRV VP4 protein is lower Low, the immune protection effect is not ideal; GCRV NS38 protein orally immunizes grass carp, although it cannot stimulate grass carp to produce a specific immune response, it can significantly improve the level of non-specific immunity of grass carp

In addition, the results of the challenge protection experiment showed that the expression of GCRV VP4 protein and GCRV NS38 protein can stimulate the fish to produce a certain immune protection effect, but the two relative protection rates are relatively low.

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