Identification of a functional Antigen5-related allergen in the saliva of a blood feeding insect, the tsetse fly

• Published in: Insect biochemistry and molecular biology Vol. 39; no. 5; pp. 332 - 341
• Main Authors: Caljon, Guy, Broos, Katleen, De Goeyse, Ine, De Ridder, Karin, Sternberg, Jeremy M., Coosemans, Marc, De Baetselier, Patrick, Guisez, Yves, Van Den Abbeele, Jan
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2009
• Subjects: Allergen; allergenicity; allergens; Allergens - genetics; Allergens - immunology; Animals; Antibodies; Antibodies - blood; Antibodies - immunology; Antigen5; antigens; binding capacity; Cell Line; complications; digestive system; disease models; Female; Glossina; Glossina morsitans morsitans; Humans; Hypersensitivity; IgE; immune response; immunoglobulin E; Immunoglobulin E - blood; Immunoglobulin E - immunology; insect biochemistry; insect bites and stings; Insect Bites and Stings - immunology; insect proteins; Insect Proteins - genetics; Insect Proteins - immunology; insect vectors; Mast cells/basophils; Mice; Mice, Knockout; risk assessment; RNA interference; saliva; Saliva - immunology; salivary glands; Salivary transcriptome; TAg5; trypanosomiasis; Tsetse Flies - genetics; Tsetse Flies - immunology; Tsetse fly; Salivary transcriptome; RNA interference; Antigen5; IgE; Hypersensitivity; Antibodies; Tsetse fly; Mast cells/basophils; Glossina; HAT; TAg5; Allergen; Sf9 cells
• ISSN: 0965-1748; 1879-0240
• DOI: 10.1016/j.ibmb.2009.01.010

Our previous screening of a Glossina morsitans morsitans λgt11 salivary gland expression library with serum of a tsetse fly exposed rabbit identified a cDNA encoding Tsetse Antigen5 (TAg5, 28.9 kDa), a homologue of Antigen5 sting venom allergens. Recombinant TAg5 was produced in Sf9 cells in order to assess its immunogenic properties in humans. Plasma from a patient that previously exhibited anaphylactic reactions against tsetse fly bites contained circulating anti-TAg5 and anti-saliva IgEs. In a significant proportion of plasma samples of African individuals, TAg5 and saliva binding IgEs (respectively 56 and 65%) can be detected. Saliva, harvested from flies that were subjected to TAg5-specific RNA interference (RNAi), displayed significantly reduced IgE binding potential. Allergenic properties of TAg5 and tsetse fly saliva were further illustrated in immunized mice, using an immediate cutaneous hypersensitivity and passive cutaneous anaphylaxis assay. Collectively, TAg5 was illustrated to be a tsetse fly salivary allergen, demonstrating that Antigen5-related proteins are represented as functional allergens not only in stinging but also in blood feeding insects.