[Anti-aspergillus Th immunity induced by dendritic cells and the effect of hydrocortisone on it]

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.

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.

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.

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.