Helminth-derived products inhibit the development of allergic responses in mice.
BACKGROUND
Epidemiological studies suggest that infections with helminths protect from the development of asthma. Supporting this view is our published finding that infection with Nippostrongylus brasiliensis decreased ovalbumin-induced Th2 responses in the lung of mice.


OBJECTIVE
To evaluate if N. brasiliensis excretory-secretory products also prevent the development of asthma.


METHODS
Mice were immunized with ovalbumin/alum intraperitoneally in the absence or presence of helminthic products and then challenged intranasally with ovalbumin. Six days later, we analyzed if the mice developed Th2 responses in the lung.


RESULTS
The application of the helminthic products together with ovalbumin/alum during the sensitization period totally inhibited the development of eosinophilia and goblet cell metaplasia in the airways and also strongly reduced the development of airway hyperreactivity. Allergen-specific IgG1 and IgE serum levels were also strongly reduced. These findings correlated with decreased levels of IL-4 and IL-5 in the airways in product-treated animals. The suppressive effects on the development of allergic responses were independent of the presence of Toll-like receptors 2 and 4, IFN-gamma, and most important, IL-10. Interestingly, suppression was still observed when the helminthic products were heated or treated with proteinase K. Paradoxically, we found that strong helminth product-specific Th2 responses were induced in parallel with the inhibition of ovalbumin-specific responses.


CONCLUSIONS
Our results suggest that helminths suppress the development of asthma by secreting substances that modulate allergic responses without affecting the generation of helminth-specific Th2 immunity. The identification of these products may lead to the design of novel therapeutic intervention strategies for the treatment of asthma.
Trujillo-Vargas
Claudia M
CM
Center for Infectious Diseases, University of Würzburg, Würzburg, Germany.
Werner-Klein
Melanie
M
Wohlleben
Gisela
G
Polte
Tobias
T
Hansen
Gesine
G
Ehlers
Stefan
S
Erb
Klaus J
KJ
D000818:Animals; D001985:Bronchial Provocation Tests; D019286:Endopeptidase K / Q000494:pharmacology; D005260:Female; D020397:Goblet Cells / Q000473:pathology; D006374:Helminthiasis, Animal / Q000276:immunology*; D007073:Immunoglobulin E / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D008679:Metaplasia / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D009559:Nippostrongylus / Q000276:immunology*; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology; D011657:Pulmonary Eosinophilia / Q000276:immunology; D012130:Respiratory Hypersensitivity / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology
D007074:Immunoglobulin G; D007073:Immunoglobulin E; D010047:Ovalbumin; D019286:Endopeptidase K