Human epithelial cells of the respiratory tract and the skin differentially internalize grass pollen allergens.
Epithelial cells of both the respiratory tract and the skin form a tight barrier against environmental harm. They represent the site of first contact for airborne allergen carriers. Consequently, in this study, we analyzed the uptake of grass pollen allergens by epithelial cells: Phl p 1 was selected as a glycosylated allergen containing disulfide bridges whereas Phl p 6 lacks post-translational modifications. Allergen uptake by the respiratory epithelial cell line A549 reached a plateau at 2 hours, and both allergens were localized intracellularly in non-acidic vesicles. In addition, in A549 cells allergens were exocytosed, suggesting a transcytosis mechanism in the passage of allergens over the respiratory epithelial barrier. In contrast, allergens were predominately localized in lysosomes in keratinocytes, and allergen uptake did not reach a plateau up to 24 hours. Notably, keratinocytes from atopic patients showed a significantly increased uptake of Phl p 1 as compared with healthy donors. Preincubation of epithelial cells with IL-4 and/or IFN-gamma to simulate inflammatory status led to an increased allergen uptake only in keratinocytes. This higher engulfment of allergens by inflammatory-type keratinocytes suggests a higher susceptibility of inflamed skin for the uptake of allergens and consequently a potentially higher risk for sensitization under natural exposure conditions, such as chronic atopic eczema.
Blume
Cornelia
C
Division of Environmental Dermatology and Allergy, ZAUM - Center for Allergy and Environment, HelmholtzZentrum München, Technische Universität Munich, Munich, Germany.
Foerster
Stefanie
S
Gilles
Stefanie
S
Becker
Wolf-Meinhard
WM
Ring
Johannes
J
Behrendt
Heidrun
H
Petersen
Arnd
A
Traidl-Hoffmann
Claudia
C
D000485:Allergens / Q000378:metabolism*; D001980:Bronchi / Q000378:metabolism*; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism*; D005089:Exocytosis; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D015603:Keratinocytes / Q000378:metabolism*; D006109:Poaceae / Q000276:immunology*; D011058:Pollen / Q000276:immunology*; D013997:Time Factors
D000485:Allergens; D015847:Interleukin-4; D007371:Interferon-gamma