Probably no one hasn’t experienced to be bite or stung by insects, although most of them are harmless while unpleasant, but, for those who are allergic to insect venoms, a single bite or sting could induce severe symptoms, sometimes even fatal.  However, not many people know who the peacebreaker here is.

Many allergens have been identified from the venoms of insects including bees, wasps, and ants; however, relatively little is known about the horseflies, the potentially economically important blood-feeding arthropods.

In 2010, the research group heads by Dr. LAI Ren (Kunming Institute of Zoology, the CAS) collected 60 000 horseflies, first purified and analyzed two new allergens, Tab a 1 and Tab a 2, from the salivary glands of the horsefly, Tabanus yao, which are of importance for the allergic reactions induced by horsefly bite and these allergens are not only found in stinging but also found in hematophagous insects (Allergy 66 (2011) 101–109/DOI:10.1111/j.1398-9995.2010.02435.x). 

Recently, another native allergen protein Tab y 1 (apyrase)with antiplatelet activity was purified from the salivary glands of the horsefly Tabanus yao by the same research group (Allergy 66 (2011) 1420–1427/DOI:10.1111/j.1398-9995.2011.02683.x). The results showed that about 70% (7/10) of patients with horsefly allergy tested positive to Tab y 1 in skin prick test; sera from 81% (30/37) of patients reacted to Tab y 1 on western blots; purified Tab y 1 reduced approximately 42% sera IgE reactivity to horsefly salivary gland extract on a competitive ELISA. Tab y 1 also upregulated the expression of CD63 and CCR3 on passively sensitized basophils by up to approximately 4.9-fold. Tab y 1 showed enzymatic activity to hydrolyze ATP and ADP, and potent antiplatelet aggregation and antithrombotic activities.

Dr. LAI’ and his colleges research first proved the presence of Ag 5-like protein (Tab a 1), hyaluronidase (Tab a 2), with IgE-binding ability and apyrase (Tab y 1) in horseflies, which enriched our understanding of anaphylactic reactions to horsefly bites, and are also of practical significance to the diagnosis and medication to the after bite symptoms, like the so-called wasp-horsefly syndrome (WHS).

Group leader: Dr. LAI Ren  email:rlai@mail.kiz.ac.cn