Serine protease activity in excretory–secretory products of Oestrus ovis (Diptera: Oestridae) larvae

• Published in: Veterinary parasitology Vol. 114; no. 4; pp. 305 - 314
• Main Authors: Tabouret, G, Bret-Bennis, L, Dorchies, Ph, Jacquiet, Ph
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 25.06.2003; Elsevier
• Subjects: Animals; Azo Compounds - metabolism; Benzoylarginine Nitroanilide - metabolism; Cattle; Chromogenic Compounds - metabolism; Collagen - metabolism; Diptera; Diptera - enzymology; Electrophoresis, Polyacrylamide Gel - veterinary; Excretory–secretory products; Hydrogen-Ion Concentration; Hydrolysis; Immunoglobulin G - metabolism; Larva - enzymology; Life Sciences; Molecular Weight; Mucins - metabolism; Myiasis - parasitology; Myiasis - veterinary; Oestrus ovis; Protease Inhibitors - pharmacology; Serine Endopeptidases - analysis; Serine Endopeptidases - chemistry; Serine Endopeptidases - physiology; Serine protease; Serum Albumin - metabolism; Sheep; Sheep Diseases - parasitology; Trypsin; Oestrus ovis; Serine protease; Trypsin; Excretory–secretory products; Diptera
• ISSN: 0304-4017; 1873-2550
• DOI: 10.1016/S0304-4017(03)00157-2

The sheep bot fly, Oestrus ovis, is a very common myiasis of nasal and sinus cavities of sheep and goats causing severe welfare and production implications. As the viability of O. ovis adult flies strictly depends on larval abilities to assimilate and to stock nutrients from the host, it was necessary to investigate proteolytic activities in larval excretory/secretory products (ESP). ESP of O. ovis larvae degrade mucosal and plasmatic components such as mucin, albumin or immunoglobulin G. A preliminary biochemical characterization, using substrate gel analysis and inhibitor sensitivity, demonstrated the presence of at least six major serine proteases (molecular weights from 20 to 100 kDa), mainly trypsin-like, secreted in the digestive tube of larvae. Their involvement in larval trophic activity and evasion from the host immune response is further discussed as O. ovis excretory/secretory serine proteases could represent potential vaccinal targets.