Characterization of Human IgE and Mouse IgG1 Responses to Allergens in Three Mosquito Species by Immunoblotting and ELISA

Abstract

Background: IgE-mediated allergic reactions caused by mosquito bites are a common problem all over the world. This study was undertaken to determine IgE levels in subjects, to elucidate human IgE and mouse IgG1 binding patterns and to investigate the cross-reactivity of salivary gland antigens with three mosquitoes. Methods: Mosquito larvae of Aedes togoi, Culex tritaeniorhynchus and Culex pipiens pallens were collected and maintained in the laboratory. Salivary gland extracts (SGE) and whole-body extracts (WBE) were prepared from female mosquitoes of each species. Mosquito-specific IgE levels in 17 subjects were measured by ELISA. Polypeptide patterns were analyzed by SDS-PAGE. Immunoblotting was performed with sensitized human and immune mouse sera, and elucidated human IgE and mouse IgG1 binding patterns to SGE. For the determination of cross-reactivity to the three types of mosquitoes, ELISA inhibition tests were performed using sera from mice sensitized by biting of A. togoi. Results: The 9 sera out of 12 with positive skin reactions to SGE of A. togoi by skin prick test showed significantly higher anti-mosquito SGE IgE levels than in those without skin reactions. Protein band patterns of the SGE and WBE of the three species were different from one another. Specific human IgE reacted to the protein in SGE of 30.5, 33, 37 and 57.5 kD from A. togoi, of 38, 43 an 68 kD from C. tritaeniorhynchus, and of 23, 33, 34, 43, 44, 60, 74 and 93 kD from C. pipiens pallens. There were specific mouse IgG1 reactions to the bands of 30.5, 33, 37 and 57.5 kD in the SGE of A. togoi. The ELISA inhibition studies disclosed almost no cross-reactivities between A. togoi, C. tritaeniorhynchus and C. pipiens pallens.Conclusions: Immunoblot analysis disclosed that allergenic proteins in the SGE of mosquitoes and their patterns were remarkably similar between human and mouse sera to the SGE of A. togoi. Species-shared allergens may not exist among the three mosquito species prevalent in Korea.

Mosquito Allergy: Immune Mechanisms and Recombinant Salivary Allergens

“…Most of the proteins in mosquito saliva are allergenic in humans [23, 46, 47, 53, 54, 55]. Using immunoblot analyses with a pooled serum from individuals allergic to mosquito bites, allergens in the saliva or salivary gland extracts from 10 world-wide distributed mosquito species were studied [47](fig.…”

Immunological Aspects of the Immune Response Induced by Mosquito Allergens

“…Fourteen IgE reactivity fractions with a molecular weight of between 23 and 93 kDa were identified using sera from allergic patients in extracts from the salivary glands of Aedes togoi , Culex tritaeniorhynchus and C. pipiens pallens . In addition, mice immunized with these extracts produced mainly IgG1 that recognized bands of 31, 37 and 57.5 kDa [17], respectively, suggesting that these antigens could play a protective immune response.…”

“…Mosquito saliva contains various substances like lysozymes, antibacterial glucosidases, anticoagulants, antiplatelet aggregating factors and vasodilators [9,10,11,12,13]. It also contains allergens that may induce local cutaneous reactions and, in some cases, a systemic response in atopic individuals [14,15,16,17]. Allergens derived from the emanations and detritus of mosquitoes are also present in the air and in house dust, and may be inhaled and induce various immune responses [18,19].…”

Mosquito Allergy and Mosquito Salivary Allergens

“…Mosquito saliva contains many biological materials which can be classified according to their functions, as follows: (a) anticlotting and antiplatelet factors and vasodilators which presumably increase the speed at which blood from the host is imbibed [24,25]; (b) substances that affect parasite transmission by arthropod vectors [26][27][28][29][30][31][32][33][34][35][36]; (c) enzymes which are associated with sugar feeding [27,28]; (d) lysozyme, which may help to control bacterial growth in the sugar meal stored in the mosquito crop [29]; and (e) immunomodulators [30,31]. Most of these substances in mosquito saliva have been identified as allergens [32][33][34].…”

“…Most of the proteins in mosquito saliva are allergenic in humans [32,34,[41][42][43][44][45]. Using SDS-PAGE and immunoblot techniques, up to 19 allergens have been found in mosquito salivary gland extracts [41] and at least 8 proteins in the saliva of Aedes aegypti have been identified as allergens which bind to the IgE of individuals who have large local allergic reactions to mosquito bites [32].…”