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Video Q&A ViewAttendees 2

Medical, Urban, and Veterinary Entomology

Section Symposium

Vector/pathogen Molecular and Cellular Interactions On-Demand Presentations

Characterization of tick saliva protein 5B, the serpin that increased significantly in response to Ixodes scapularis tick feeding, and secreted by Borrelia burgdorferi infected nymphs

On-Demand
On-Demand
Ticks are very old creatures. To maintain such long survival, ticks develop excellent strategies for its successful feeding and disease transmission. Saliva proteins are those amongst the first components ticks inject into the host during the blood meal. Through studying tick saliva protein secretion profile, we found Ixodes scapularis saliva protein 5B, one of tick serine protease inhibitors (serpin), increases significantly in response to feeding, and is highly secreted by Borrelia burgdorferi infected I. scapularis nymphs. Enzymatic activity of 5B was profiled against a panel of 17 serine proteases related to inflammation, blood clotting, and other immune defense system pathways. Our data showed 5B was an inhibitor of Trypsin (97.9%) and multiple blood clotting factors except Thrombin. When complexed with heparin, 5B increased anti-coagulant activity, delayed plasma clotting from 404.4, 185.4, and 474.6s in heparin, 5B, and 5B and heparin incubated separately to 532.9s. Our data also shows that the position of Histidine tag that is used for affinity purification affects the inhibitory function of recombinant 5B (r5B). The C-terminal histidine tagged r5B has the highest enzymatic activity, inhibiting Trypsin and Factor Xa at 96.3.7% and 71.8% inhibition rate. However placing the His-tag at the amino terminus end reduces inhibitory activity against Trypsin and Factor Xa to 87.7% and 48.8% and recovers to 90.9% and 69.7% when the His-tag is cleaved.Our study results show that 5B could be a potential vaccine candidate against tick and tick feeding, or an anti-blood clotting treatment in combination with heparin