Dectin-1 deficiency affects immunity and tolerance to Aspergillus in HSCT mice. Dectin-1 KO mice on both genetic backgrounds were used as (B) recipients, (C) donors, or (D) both in an experimental model of HSCT in which lethally irradiated recipient mice are infused with T cell-depleted donor cells and infected with A conidia intratracheally a week later. Fungal growth (CFU ± SE), lung histology (PAS staining; bars represent magnifications), and cytokine gene expression in the lungs by real-time RT-PCR were assessed 3 days after the infection. None indicates uninfected transplanted mice. For histology, paraffin-embedded tissues (3-4 μm) of lung were stained and mounted with Eukitt mounting medium (Sigma-Aldrich). Histology sections were observed under a 20×/0.40 objective lens using an Olympus BX51 microscope (Olympus). All images were captured using a high-resolution Olympus DP71 camera (Olympus) and digitally acquired using Cell⋀P software (Version 3.3 build 2108, Olympus). Subsequent image editing was performed using Adobe Photoshop CS3 (Version 10.0, Adobe Systems Incorporated). Note the exuberant inflammatory cell responses in the lungs of recipient KO and of both donor/recipient KO as opposed to the mild inflammatory parenchymal reaction observed in (A) control WT mice or (C) donor KO. Data are representative of 2 experiments.