Functional Analysis of a Cross-tick Species Conserved Amblyomma americanum Serine Protease Inhibitor 39

Abstract

Hard ticks such as Amblyomma americanum are pool feeders that accomplish feeders by lacerating host tissue and then sucking host blood that bleeds into the wounded area. Host defense mechanisms to tick feeding activity are serine protease mediated pathways, blood clotting and inflammation that are controlled by serpins. It’s hypothesized that ticks utilize serpins to evade host defense mechanisms to successfully feed and transmit disease agents. As part of a long-term goal to understand role(s) of A. americanum serpins in tick feeding regulation, the goal of this research was to produce a recombinant (r) of a highly cross-tick species conserved A. americanum serpin, AAS39 in yeast and insect cells. The mature protein open reading frame was amplified and successfully cloned into the yeast expression plasmid, but the not insect cell plasmid. The yeast plasmid was used to transform Pichia pastoris yeast cells and rAAS39 was successfully expressed and affinity purified. Results from this research sets up the stage for follow up experiments to characterize the role(s) of rAAS39 in tick feeding regulation.