Structural and immunologic cross-reactivity among filarial and mite tropomyosin: Implications for the hygiene hypothesis - 10/08/11
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Abstract |
Background |
The hygiene hypothesis suggests that parasitic infection modulates host immune responses and decreases atopy. Other data suggest parasitic infections may induce allergic responsiveness.
Objective |
To assess the structural and immunologic relationships between the known Dermatophagoides pteronyssinus (Der p 10) tropomyosin allergen and filarial tropomyosin of Onchocerca volvulus (OvTrop).
Methods |
The molecular, structural, and immunologic relationships between OvTrop and Der p 10 were compared. Levels of OvTrop-specific and Der p 10–specific IgE, IgG, and IgG4 in sera of filaria-infected and filarial-uninfected D pteronyssinus–atopic individuals were compared, as were the responses in nonhuman primates infected with the filarial parasite Loa loa. Cross-reactivity was compared by antigen-mediated depletion assays and functionality by passive basophil sensitization.
Results |
Filarial and mite tropomyosins were very similar, with 72% identity at the amino acid level, and overlapping predicted 3-dimensional structures. The prevalence of IgE and IgG to Der p 10 was increased in filaria-infected individuals compared with uninfected subjects. There was a strong correlation between serum levels of Ov- and Der p 10–tropomyosin—specific IgE, IgG, and IgG4 (P < .0001; r > 0.79). Preincubation of sera from anti–Der p 10—positive subjects with OvTrop completely depleted IgE, IgG, and IgG4 anti–Der p 10. Basophils sensitized with sera from individuals allergic to Der p 10 released histamine similarly when triggered with OvTrop or Der p 10. Primates experimentally infected with L loa developed IgE that cross-reacted with Der p 10.
Conclusion |
Filarial infection induces strong cross-reactive antitropomyosin antibody responses that may affect sensitization and regulation of allergic reactivity.
Le texte complet de cet article est disponible en PDF.Key words : Allergy, antibody cross-reactivity, Dermatophagoides pteronyssinus, filariasis, hygiene hypothesis, tropomyosin
Abbreviations used : BMA, Fil+, Fil–, Fil-A, Fil-NA, GM, GST, HDM, Ni-A, Ni-NA, OR, OvTrop, RR
Plan
Supported by the Intramural Research Program, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health. |
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Disclosure of potential conflict of interest: The authors have declared that they have no conflict of interest. |
Vol 127 - N° 2
P. 479-486 - février 2011 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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