Secretory expression and purification of human surfactant protein A1 in Methylotrophic Yeast Pichia pastoris

Objective:To study the secretory expression,purification of human surfactant protein A1 and preliminary analysis of its antigenicity. Methods: SP A1 was cloned into the plasmid pPIC9K of P. pastoris to obtain secretory plasmid pPIC9K/SP A1. P. pastoris GS115 and KM71 were transformed by pPIC9K/SP A1, the high copy strains were selected by G418. The products of protein SP A1 were purified by affinity chromatography, and were used to immunize mice. The antigenicity of SP A1 was analyzed by ELISA and western blotting. Results:The expression levels of SP A1 were 200 mg/L in 1 L shake flask. The purity of the purified protein was about 95%. Anti SP A polyclonal antibodies specifically recognized protein SP A1,and the products can stimulate mice to produce antibodies. Conclusion:The human tissue specific protein SP A1 was highly expressed in Methylotrophic Yeast P. pastoris and showed satisfied antigenicity.