Hemalin from Haemaphysalis flava ticks: cloning, expression and antithrombogenicity
1College of Veterinary Medicine, Hunan Provincial Key Laboratory of Protein Engineering in Animal Vaccines, Hunan Collaborative Innovation Center for Safety Production of Livestock and Poultry, Hunan Agricultural University, Changsha, China.
Medical and Veterinary Entomology
|August 5, 2020
Summary
Hemalin from Haemaphysalis flava exhibits anticoagulant properties, similar to its counterpart in Haemaphysalis longicornis. This study characterized the Hf-hemalin protein, confirming its anticoagulant activity and potential for tick vaccine development.
Area of Science:
- Parasitology
- Molecular Biology
- Biochemistry
Background:
- Hemalin is a known anticoagulant protein found in the tick Haemaphysalis longicornis.
- The presence and function of hemalin in Haemaphysalis flava remained uncharacterized.
- Tick salivary proteins play crucial roles in host-parasite interactions, including modulating blood coagulation.
Purpose of the Study:
- To clone and characterize the full-length hemalin gene (Hf-hemalin) from Haemaphysalis flava.
- To express and purify the recombinant Hf-hemalin protein (rHf-Hemalin).
- To evaluate the antithrombotic activity of rHf-Hemalin.
Main Methods:
- Cloning of full-length Hf-hemalin using 3'-end rapid amplification of cDNA ends (RACE).
- Prokaryotic expression of Hf-hemalin in Escherichia coli.
- Assessment of antithrombogenicity by measuring prothrombin time (PT) and activated partial thromboplastin time (aPTT) in rat plasma.
Main Results:
- The full-length Hf-hemalin cDNA is 607 bp with an open reading frame (ORF) of 423 bp, predicted to encode a protein with Kunitz domains and a signal peptide.
- Recombinant Hf-Hemalin (rHf-Hemalin) was successfully expressed and purified.
- Incubation with rHf-Hemalin significantly prolonged PT and aPTT in rat plasma, indicating anticoagulant activity.
- Hf-hemalin expression was higher in semi-engorged ticks compared to fully engorged ones.
Conclusions:
- Hemalin from H. flava shares structural similarities and anticoagulant function with H. longicornis hemalin.
- The characterized Hf-hemalin demonstrates significant antithrombotic properties.
- Further research is warranted to explore Hf-hemalin as a potential antigen for anti-tick vaccine development.
