Expression Of Recombinant S2 Domain Of Spike Protein Of Porcine Epidemic Diarrhea Virus

Porcine epidemic diarrhea virus (PEDV) is the causative agent of severe watery diarrhea in suckling piglets. PEDV outbreaks have been consistently reported in Europe, Asian countries and Thailand. The recombinant protein, especially the spike (S) protein, from field strain PEDV could be used to develop a sensitive diagnostic test or an effective vaccine. In this study, the recombinant S2 domain protein from the PEDV Thai isolate was expressed using the E. coli expression system. The full length S2 domain of the S gene of the PEDV G2b Thai isolate was amplified using a PCR technique and was cloned into the pBAD Directional TOPO (R) expression vector. For the expression of the whole recombinant S2 domain protein, the optimum concentration of arabinose was 0.002% and the optimum induction time was 6 hours. Based on SDS-PAGE, the size of the whole recombinant S2 domain protein bands was approximately 90 kDa. The whole recombinant S2 domain protein showed specific interaction with mouse anti-histidine monoclonal antibody and rabbit polyclonal antibody against PEDV Gla. The ability of the whole recombinant S2 domain protein in this study to react with antibody induced by different PEDV genogroup (Gla) showed the potential for using this whole recombinant S2 domain protein to detect PEDV infection or to induce antibodies against different PEDV genogroups. According to this study, the whole recombinant S2 domain protein may be a useful tool for the development of a diagnostic test for PEDV or for a vaccine against PEDV.