Objective: To investigate the role of dendritic cells (DCs) in host defense against aspergillus, and how corticosteroids hydrocortisone (HC) affects host anti-aspergillus immunity at the DCs level.
Methods: Mouse bone marrow-derived DCs were generated ex vivo and the uptake of inactivated Aspergillus fumigatus conidia (iAfc) by DCs was assayed using McFarland standard. Cytokine production by DCs or by splenic T cells were measured using ELISA method.
Results: DCs were capable of ingesting iAfc efficiently. HC significantly inhibited the capacity of DCs to phagocytose iAfc. After stimulated with iAfc in vitro, DCs secreted IL-12 and IFN-gamma, but did not secret IL-10. 10(-5) mol/L HC down-regulated IL-12 and IFN-gamma production by DCs, but it didn't affect IL-10 production. After the mice were inoculated with iAfc-pulsed DCs, their splenic T cells secreted IFN-gamma upon the re-stimulation with iAfc in vitro. In contrast, after the mice were inoculated with iAfc-HC-pulsed DCs, the splenic T cells showed significantly decreased IFN-gamma secretion upon the same stimulation, but the secretion of IL-10 was increased.
Conclusions: DCs might act as effector cells in host defense against aspergillus, and initiate anti-aspergillus Th1 type immunity. HC inhibited the above functions of DCs and skew the immunity response towards Th2 type. iAfc-pulsed DCs might be useful for promoting the anti-aspergillus immunity of immunocompromised host.