Prokaryotic Expression Of Bovine Viral Diarrhea Virus The Envelope Protein E^rns/E2and Construct Phage Display Anti-BVDV Nanobody Library

Bovine viral diarrhea/mucosal disease (BVD-MD), caused by BVDV is an acute feverish and highly contagious disease. The main clinical characters of the disease are mucosal inflammation, erosion, necrosis and diarrhea. The disease is widely spreaded in the world, expecially in Europe and the United States, other developed countries. The disease causes serious economic losses for both dairy and beef industries worldwidely. Since1980, our country find the diease and identified the the virus when instruction of cows from other countries. Because of neither adoption of measures to control of BVDV nor BVDV vaccine applied,except for slaughter. So it is crucial to find a new pathway for preventing and curing BVD-MD.Since the advent of hybridoma technology, antibodies have been widely used in the diagnosis and treatment of the disease. It seems that antibody for the treatment of the disease have unlimited potential, because we do not worry about their toxicity. Traditional monoclonal antibody, however, still exist a variety of defects, such as:the volume is large, poor stability, preparation process cumbersome, cost high, need to be humanized and so on. There is a special kind of natural lack of light chain, heavy chain antibody in Camelids and sharks. The heavy chain antibody with variable region is called single domain antibody, also known as nanobodies. The variable region is a small volume,high solubility and stability, easy to production,and identify epitopes that is in the grooves or gaps, According to the virtue of the nanobodies, It has been widely used in clinical diagnosis and treatment.According to the strain of BVDV-NADLstandard sequence in GenBank, designed the primers of Erns(E0)、E2gene.The pET-32a-Erns and pET-32a-E2vector was successfully constructed.Recombinant Erns、E2was synthesized by transforming the pET-32a-Erns、pET-32a-E2transfected into BL21(DE3)competent cells.The expression product was detected by SDS-PAGE and Western blot.BVDV stain was grown in MDBK cell lines, and then harvested after72hours.Xinjiang Camelus bactrianus was immunized with the inactivated virus. The VHH fragments was amplified from the cDNA by nest-polymerase chain reaction and assembled into phage display vector. The library was constructed by transforming the vector into TG1competent cells. Super-infected with M13KO7helper phage containing the heavy chain antibody variable region sequence of the TG1bacteria, to construct the phage display anti-BVDV nanobody library. Lay the foundation for subsequent nanobody screening against bovine viral diarrhea virus.This test build of bovine viral diarrhea virus envelope protein Erns d E2the prokaryotic expression vector induced expression of the target protein45KD、64KD, high purity protein purified protein by Ni-NTA purification device.They have good reactionogenicity by Western-Blot.cDNA as a template, amplification heavy chain antibody variable region sequences from camel, building a storage capacity of4.32×105initial library.After helper phage rescue,the phage display library was generated with the titre up to1.3×1011CFU/mL. Lay the foundation for using the BVDV envelope glycoprotein Erns, E2as antigen screening with high affinity and high specificity antibodies against BVDV.