Endogenous interleukin-10 suppresses allergen-induced airway inflammation and nonspecific airway responsiveness.
BACKGROUND
The airway inflammation observed in asthma is orchestrated by activated Th-2 lymphocytes relevant for the induction of altered airway responsiveness. An increasing body of evidence is accumulating that not only the pro-inflammatory cytokines interleukin (IL)-4 and IL-5 but also the immunomodulating cytokines IL-12 and possibly IL-10 are crucial for regulating the allergic airway inflammation.


OBJECTIVE
Since IL-10 is capable of downregulating a broad spectrum of pro-inflammatory cytokines, we wanted to address the role of endogenously produced IL-10 in vivo in allergic asthma.


METHODS
Knockout (IL-10(-/-)) mice (C57BL/6-IL10tm1Cgn) and wild-type (WT) counterparts were immunized (day 0) and exposed (day 14-21) to ovalbumin (OVA). Airway inflammation and reactivity (AR), serum allergen-specific IgE responses and cytokine profiles in the bronchoalveolar lavage fluid (BALF) were studied.


RESULTS
The IL-10(-/-) mice had more eosinophilic airway inflammation but comparable levels of allergen-specific serum IgE compared to the WT mice after allergen challenge. The AR was comparably increased in the OVA challenged WT and IL-10(-/-) mice vs sham-exposed WT, but not vs sham-exposed IL-10(-/-)mice since these showed a higher baseline AR. IFN gamma, IL-4 and IL-13 were comparable and IL-5 was even lower in the BALF of the in IL-10(-/-) mice compared to the similarly exposed WT mice.


CONCLUSIONS
These results indicate that IL-10 plays an important and possibly direct role in the control of airway inflammation and responsiveness in an in vivo mouse model of allergy.
Tournoy
K G
KG
Department of Respiratory Diseases, Gent University Hospital, Gent, Belgium.
Kips
J C
JC
Pauwels
R A
RA
D000485:Allergens / Q000276:immunology*; D000818:Animals; D001249:Asthma / Q000276:immunology*; D016535:Bronchial Hyperreactivity / Q000276:immunology*; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D002217:Carbachol / Q000494:pharmacology; D016207:Cytokines / Q000096:biosynthesis; D004195:Disease Models, Animal; D005856:Germ-Free Life; D007073:Immunoglobulin E / Q000097:blood; D007249:Inflammation / Q000276:immunology; D016753:Interleukin-10 / Q000276:immunology* / Q000378:metabolism; D008168:Lung / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology
D000485:Allergens; D016207:Cytokines; D016753:Interleukin-10; D007073:Immunoglobulin E; D002217:Carbachol; D010047:Ovalbumin