We describe a strategy to monitor maturation and migration of pulmonary dendritic cells in response to ovalbumin in the setting of ovalbumin induced allergic airway inflammation. This strategy can be modified to assess migration of pulmonary dendritic cells in settings of infection.
Dendritic cells (DCs) are the key players involved in initiation of adaptive immune response by activating antigen-specific T cells. DCs are present in peripheral tissues in steady state; however in response to antigen stimulation, DCs take up the antigen and rapidly migrate to the draining lymph nodes where they initiate T cell response against the antigen1,2. Additionally, DCs also play a key role in initiating autoimmune as well as allergic immune response3.
DCs play an essential role in both initiation of immune response and induction of tolerance in the setting of lung environment4. Lung environment is largely tolerogenic, owing to the exposure to vast array of environmental antigens5. However, in some individuals there is a break in tolerance, which leads to induction of allergy and asthma. In this study, we describe a strategy, which can be used to monitor airway DC maturation and migration in response to the antigen used for sensitization. The measurement of airway DC maturation and migration allows for assessment of the kinetics of immune response during airway allergic inflammation and also assists in understanding the magnitude of the subsequent immune response along with the underlying mechanisms.
Our strategy is based on the use of ovalbumin as a sensitizing agent. Ovalbumin-induced allergic asthma is a widely used model to reproduce the airway eosinophilia, pulmonary inflammation and elevated IgE levels found during asthma6,7. After sensitization, mice are challenged by intranasal delivery of FITC labeled ovalbumin, which allows for specific labeling of airway DCs which uptake ovalbumin. Next, using several DC specific markers, we can assess the maturation of these DCs and can also assess their migration to the draining lymph nodes by employing flow cytometry.
The method presented here offers a flow cytometry based approach for analyzing pulmonary DCs, based on delivery of OVA-FITC for airway challenge. This allows for selective monitoring of pulmonary DCs, which take up OVA-FITC and therefore the DC populations, which are monitored are effectively the ones that are participating in the airway immune response during the course of OVA-induced allergic airway inflammation. In control mice, in the absence of allergic airway inflammation, the numbers of migratory DCs (OVA-FITC+ DC…
The authors have nothing to disclose.
This work was funded by CIHR and CF Canada grants to Dr. Jim Hu and by a PhD studentship awarded to Rahul Kushwah by CF Canada.
Name of the reagent | Company | Catalogue number |
Ovalbumin | Sigma-Aldrich | A5503 |
Alum | Thermo Scientific | 77161 |
OVA-FITC | Sigma-Aldrich | A9771 |
Collagenase D | Roche | 11088858001 |
Antibodies | e-Bioscience |