Migration and accumulation of eosinophils toward regional lymph nodes after airway allergen challenge.
BACKGROUND
Eosinophils play a major role in allergic airway inflammation because of their ability to release toxic mediators. In addition, they are able to migrate toward draining thoracic lymph nodes (TLNs) after intratracheal administration, where they can function as antigen-presenting cells.


OBJECTIVE
In this study, we evaluated in vivo eosinophil migration toward the TLN after allergen sensitization and analyzed expression of molecules involved in antigen presentation.


METHODS
Mice were sensitized by intraperitoneal injection of ovalbumin on days 1 and 10 and challenged once intranasally with ovalbumin on day 20. The kinetics of eosinophilia was evaluated in blood, lung tissue homogenate, bronchoalveolar lavage fluid, and TLN. Cell surface staining was analyzed by flow cytometry.


RESULTS
The kinetics of eosinophil recruitment was similar in TLN, lung tissue, and blood, beginning at 12 hours and peaking at 48 hours after allergen challenge. Approximately 70% of TLN eosinophils expressed MHC class II molecules, compared with less than 25% in blood and lungs. Moreover, TLN eosinophils expressed higher levels of MHC class II and CD86 compared with blood and lung eosinophils. Most eosinophils expressed CD80 and CD54, whereas only a few eosinophils expressed CD40. Eosinophils in lungs and TLN appeared to be activated with lower CD62-ligand expression compared with blood eosinophils.


CONCLUSIONS
The presence of eosinophils with a different phenotype in the TLN at early time points after allergen challenge of sensitized mice supports their capacity to serve as antigen-presenting cells, sustaining allergic/inflammatory responses in the airways.
Department of Pediatrics, Division of Basic Sciences, National Jewish Medical and Research Center, Denver, CO 80206, USA.
Catherine
C
Duez
Azzeddine
A
Dakhama
Adrian
A
Tomkinson
Philippe
P
Marquillies
Annette
A
Balhorn
André-Bernard
AB
Tonnel
Donna L
DL
Bratton
Erwin W
EW
Gelfand
D000280:Administration, Inhalation; D000485:Allergens / Q000008:administration & dosage / Q000276:immunology*; D000818:Animals; D017951:Antigen Presentation / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology; D001985:Bronchial Provocation Tests; D002634:Chemotaxis, Leukocyte / Q000276:immunology*; D004804:Eosinophils / Q000276:immunology*; D005260:Female; D005802:Genes, MHC Class II / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology*; D051379:Mice; D013909:Thorax
D000485:Allergens; D015703:Antigens, CD