IL-10 desensitizes Th17 cells memorized with Candida antigen (34.9)

Abstract Th17 cells are important effector cells in host resistance against C. albicans infection. Here, we demonstrated the desensitization of Th17 cells memorized with C. albicans in severely burned patients. Under stimulation with the Candida antigen, T cells with abilities to produce IL-17, to express RORγt and to be proliferative were considered to be Th17 cells memorized with Candida antigen. PBMC (2 x 106 cells/ml), isolated from burn patients (> 30% TBSA burn), were stimulated with Candida antigen (heat-killed C. albicans) for 3 days. Culture fluids obtained were assayed for IL-17, and cells harvested were analyzed for expression of RORγt. The proliferative response of these PBMC stimulated with the antigen was tested by BrdU proliferation kit. In the results, as compared with healthy donor PBMC, the decreased amounts of IL-17 were produced, and RORγt was not expressed by patient PBMC. The proliferation of burn patient PBMC stimulated with the antigen was greatly decreased as compared with that of controls (326 ± 32% vs. 86 ± 15%). Burn patient serum (15%) inhibited the proliferation of healthy donor PBMC stimulated with the antigen. IL-10 was detected in burn patient serum, and burn patient serum treated with anti-IL-10 mAb did not inhibit the proliferation of Th17 cells stimulated with the antigen. These results indicate that T cells memorized with Candida antigen are desensitized in severely burned patients. IL-10 is indicated as an effector of this desensitization.