Horseflies (Tabanus yao) are mainly distributed in pastoral area and bite human and livestock. A bite from a horsefly can be very painful, and it can cause allergic reactions in humans. There is no information about allergenic horsefly proteins.
Professor Ren LAI of Kunming Institute of Zoology (KIZ) , the Chinese Academy of Sciences (CAS), and his Ph.D student Dong-ying MA, purified and characterized two IgE-binding proteins, Tab a 1 and Tab a 2 with molecular weight of 26 and 35 kD, from horsefly salivary glands of T. yao. Immunoblotting demonstrated IgE binding by 32 and 34 of 37 subjects’ sera to Tab a 1 and Tab a 2, respectively. They were identified as an antigen 5-related (Ag 5) protein and hyaluronidase, respectively. In addition, these two proteins showed some IgE-binding capacity to sera of subjects with wasp sting allergy. These results provided support for the presence of the so-called wasp-horsefly syndrome (WHS), and were very important to insect allergies.
The finding was published in Allergy, European Journal of Allergy and Clinical Immunology(http://www3.interscience.wiley.com/journal/123573198/abstract).