ABSTRACT: DCs are localized under the mucosa of the lungs and the gastrointestinal tract, and therefore come into close contact with A. fumigatus germ tubes during early steps of infection as soon as fungi become invasive. For a more detailed insight into differentially regulated genes, whole genome microarray analysis was performed. On average, unstimulated DCs showed expression of about 13.500 genes (35% of all genes spotted on the chip). After 6h co-cultivation of DCs and live A. fumigatus germ tubes, 590 genes showed a 4fold altered gene expression, if normalizing data with VSN before. Therein, a wide range of immune response genes, including genes encoding for cytokines (IL-1α, IL-1β, IL-6, IL-8, IL-10, IL-12p40, TNF-α), chemokines (CCL5, CCL20, CXCL10), immunorelevant receptors (TLR2, TLR4, PTX-3), as well as costimulatory molecules (CD40, CD80, CD83, CD86) were differentially regulated. Experiment Overall Design: Human DCs were generated from two independent, healthy blood donors. 5 x 106 DCs were either cultivated without fungi or together with 5 x 106 A. fumigatus germ tubes for 6h until isolation of total RNA.