Efficient production of nanobodies against urease activity ofHelicobacter pylori in Pichia pastoris

Helicobacter pylori is a major health problem. One of the therapeutic approaches is administration of antibody against H. pylori. The methylotrophic Pichia pastoris is a suitable host for expression of recombinant antibody fragments. The aims of this study were the expression and the evaluation of camelid nanobody in the yeast Pichia pastoris.The camelid-derived heavy-chain antibody (nanobody) against the UreC subunit of urease from H. pylori was subcloned in the pPink-HC shuttle vector and transferred into Escherichia coli TOP10. After digestion and purification, the shuttle vector was transformed in the PichiaPink expression system. The expression was evaluated in an in vitro system.The yield of the nanobody expressed in P. pastoris was estimated to be 5 mg/L as compared to 2 mg/L expressed by E. coli. The nanobody was purified and binding affinity to the UreC antigen was evaluated using ELISA. Neutralization abilities of the two nanobodies expressed in yeast and E. coli were compared. The yeast-expressed nanobody specifically detected recombinant UreC and inhibited urease activity with high efficiency.The results suggest attribution of the enhanced quality and quantity of the nanobody produced in P. pastoris to better posttranslational modification and folding in the yeast cell.