Expression of porcine interleukin-2 in Escherichia coli

A mature form of porcine interleukin-2 (IL-2) protein without signal peptides was expressed as glutathione S-transferase (GST) fusion proteins in Escherichia coli using pGEX vector. Since most of GST-IL-2 fusion protein was detected in an insoluble fraction on SDS-PAGE analysis, the insoluble fusion protein was solubilized by refolding procedure using urea. The recombinant IL-2 (rIL-2) was purified by a batch method using Glutathione Sepharose 4B and factor Xa digestion and used for preparation of antisera in mice. The antisera reacted with rIL-2 expressed in baculovirus system on immunoblot analysis. In addition, the purified rIL-2 showed a high biological activity on CTLL-2 proliferative response.