Expression of recombinant S2 domain of Spike protein of Porcine epidemic diarrhea virus

Abstract

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® 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 G1a. The ability of the whole recombinant S2 domain protein
in this study to react with antibody induced by different PEDV genogroup (G1a) 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.