Thymosin α 1 activates human DCs on exposure to A fumigatus MDCs and PDCs were obtained from blood mononuclear cells. For phagocytosis (A), see legend to Figure 1. The data are the means ± SEs of 3 independent experiments and expressed as the percentage of internalization (numbers within figures). ^*P < .05, thymosin-exposed versus unexposed cells. Cells were stained with Diff-Quik stain (Carlo Erba Reagents, Milan, Italy). Original magnification, ×100. (B) Cytokines were determined in 24-hour culture supernatants of DCs stimulated (+) or not (-) with thymosin α 1 in the presence of conidia or CpG 2006 (3 μg/mL). Bars indicate the standard errors. ^*P < .05, cytokine production in thymosin-exposed versus unexposed cells. ^**P < .05, thymosin + CpG versus CpG alone.