World Allergy Organization Journal (Feb 2020)

Novel salivary gland allergens from tropical mosquito species and IgE reactivity in allergic patients

  • Anunya Opasawatchai,
  • Watchareewan Yolwong,
  • Walairat Thuncharoen,
  • Nanthicha Inrueangsri,
  • Sulak Itsaradisaikul,
  • Cherapat Sasisakulporn,
  • Wanlapa Jotikasthira,
  • Oranart Matangkasombut,
  • Onrapak Reamtong,
  • Wiparat Manuyakorn,
  • Wisuwat Songnuan,
  • Ponpan Matangkasombut

Journal volume & issue
Vol. 13, no. 2

Abstract

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Background: Mosquito allergy is common in tropical countries but remains under-diagnosed. This may be due to the lack of knowledge and diagnostic tools for tropical mosquito allergens. Objective: We aimed to characterize allergens from tropical mosquito species and investigate IgE reactivity in mosquito-allergic patients to the salivary gland proteins from these mosquitoes. Methods: Salivary gland extract (SGE) from 4 mosquito species, highly distributed in the tropics, including Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles dirus b, were studied. SGE-specific IgE and IgG ELISA were developed, and serum from 64 mosquito-allergic and 22 non-allergic healthy control subjects was assayed. Further investigations using IgE-immunoblots followed by mass spectrometry analysis were performed to identify and characterize allergens from each species. Results: Mosquito-allergic subjects have detectable serum IgE to SGE derived from local mosquito species, while the IgE levels to Aedes communis using commercially available ELISA were mostly minimal. IgE-immunoblot analysis and mass spectrometry identified 5 novel mosquito allergens from A. albopictus (Aed al 2, Aed al 3), C. quinquefasciatus (Cul q 2.01, Cul q 3), and A. dirus b (Ano d 2). Interestingly, 4 of the 5 new allergens belong to the D7 protein family. Conclusions & clinical relevance: Five novel allergens from 3 tropical mosquito species were characterized. The majority of mosquito-allergic subjects who live in the tropics have IgE reactivity to these allergens. Our study paves the way for the development of diagnostic tests, component-resolved diagnostics, and future immunotherapy for mosquito allergy in tropical countries. Keywords: Allergens, Insect allergy, IgE, Mosquito, Tropical species