Expression-in-Pichia pastoris of gene fragment encoding porcine CD8α extracellular domain

To prepare porcine CD8α recombinant protein with higher biological activity,porcine CD8α molecule extracellular domain gene fragment(pCD8α-ED)was amplified by PCR from the recombinant plasmid pGEM-T-pCD8α,and cloned into pPIC9K vector to express pCD8α-ED in Pichia pastoris.The expression conditions were optimized and the results showed that the recombinant strain could express recombinant protein with a molecular weight of 20ku,the optimal pH was 5.0,and the optimal induction time was 120h.Western-blot analysis showed that it had a specific band of 20ku,demonstrating that the protein of pCD8α-ED possessed immunological activity.