Thymosin α 1 activates the MyD88-dependent pathway of TLR signaling. (A) Production of IL-12 p70 and IL-10 by murine lung DCs on exposure to TLR ligands and/or thymosin α 1. Zym (zymosan, 10 μg/mL), LTA (1 μg/mL), Poly(I:C) (10 μg/mL), LPS (1 mg/mL), and unmethylated CpG 1826 (CpG, 2 μM) are shown. ^*P < .05, cytokine production in the presence (+) or not (-) of thymosin α 1. Bars indicate the standard errors. (B) Production of IL-12 p70 and IL-10 from lung DCs from wild-type (□) or MyD88-deficient (▪) mice, on exposure to conidia and/or thymosin α 1. Bars indicate the standard errors. ^*P < .01, cytokine production in MyD88-deficient versus wild-type mice. (C) Mice were intranasally infected with Aspergillus conidia and treated with thymosin α 1 for 5 consecutive days, beginning the day of the infection. The fungal growth (chitin content of the lungs) was assessed a day after treatment. Bars indicate the standard errors. ^*P < .05, treated versus untreated mice. ^**P < .05, MyD88-deficient versus wild-type mice.