Tα 1 promotes mobilization and Th1/Treg antifungal priming of human DCs. (A) Surface expression of CD11c, CD1a, and CD123 on DCs derived from peripheral CD14⁺ cells of different donors with GM-CSF/IL-4 (GM-DCs) or FLT3L (FL-DCs) in the presence of Tα1. Percentage of positive cells is indicated. (B) Phagocytosis of conidia by GM- or FL-DCs exposed (+) or not (–) to Tα1 from 7 recipients of T-cell–depleted haploidentical HSC transplants. The data are the means ± SE and are expressed as percentage internalization (numbers within panels). *P < .05, Tα1-treated versus untreated cells. Visualized with a 100×/1.25 oil-immersion objective lens. (C) Cytokine production (pg/mL by ELISA) by Tα1-induced DCs, from healthy donors, cultured in serum-free medium (1 × 10⁶ cells/mL) with unopsonized Aspergillus conidia (5 × 10⁵/mL), 10 μg/mL zymosan, or 2 μg/mL CpG-B ODN 2006 for 24 hours. The data shown are aggregated results from 3 independent experiments and are presented in the mean ± SD. The detection limits of the assays were as follows: less than 3 for IL-12p70, less than 5 for IL-10, and less than 3 for IFN-α. (D) Cytokine production by peripheral blood Aspergillus-specific CD4⁺ T-cell clones from healthy donors in response to Aspergillus-pulsed Tα1-treated DCs as in panel A. Bars indicate standard errors. The detection limits (pg/mL) of the assays were less than 0.5 for IL-4 and IFN-γ.*P < .05, conidia-stimulated versus unstimulated cells. **P < .05, Tα1-exposed versus unexposed cells. (E) Frequency of Aspergillus-specific or alloreactive T-cell clones responding to the different types of fungus-pulsed DCs or unpulsed DCs, respectively, from healthy donors or transplant recipients. Growing clones were assessed for specificity after 2 days of stimulation with DCs. *P < .05, GM-DCs versus peripheral blood cells (–). **P < .05, HSCT-DCs versus all other DCs. nd indicates not done.