Expression Of The S2 Gene Of A Chinese EIAV Strain In E. Coli And Development Of Polyclonal Antibodies Against The S2 Protein

Equine infectious anemia virus (EIAV), a member of lentivirus family which related with human immunodeficiency virus, causes a life-long infection and chronic disease in horses characterized by periodic episodes of fever, plasma viremia, anemia, and thrombocytopenia.EIAV is the simplest framework lentivirus. In addition to the gag, pol, and env genes, which are present in the genomes of all retroviruses, EIAV contains only three auxiliary genes, the tat and rev genes, which are common to all lentiviruses, and the novel S2 gene, which is of unknown function and does not evidently correspond to any known lentivirus accessory gene. Previous studies demonstrate thepresence of serum antibodies to S2-specific peptides in EIAV-infected horses, but the function of S2 gene is unknow. Analyzing S2 gene sequence find that there is guge difference between velogenic strain and vaccine strain.The difference of nucleotide and amino acids is 4.1% and 10.4%. However, recent studies from our lab demonstrate that the S2 gene is not essential for virus replication in vitro. , a virus lacking S2 was less pathogenic in ponies, showing a less severe platelet reduction compared with wildtype in vivo The expression of the antigenic specific EIAV S2 protein and the preparation of its polyclonal antibody established essential materials for further study on the function of EIAV S2 gene in viral replication and pathogenesis.In this study, To study the function of equine infectious anemia virus (EIAV) S2 accessory protein, the S2 gene of a Chinese EIAV strain EIAVFDDV3-8 was amplified by PCR and cloned into the pMD-18T vector. After sequencing analysis, the S2 gene was then subcloned into a prokaryotic expression vector and was expressed in E. coli as a fusion protein with the 6xHis tag. The predicted 20 kDa recombinant protein ,whith expressed efficiently in form of inclusion body, was expressed in transferred E. coli by the introduction with IPTG, The recombinant S2 was purified by nickel affinity chromatography and was used to immunize rabbits for preparing an anti-S2 antibody. Then the antiserum was tested by western blot. As a result, the antiserum had a positive.This laid a solid foundation and prepared experimental material for the future studies on S2 antibody and S2 protein.