Pulmonary findings 17 to 21 days after intratracheal instillation of A fumigatus conidia in X-CGD mice. Lung tissue was obtained 17 to 21 days after intratracheal challenge with 150 to 500 A fumigatus conidia, and stained with hematoxylin and eosin (A and C) or Grocott methamine silver (B). Representative photomicrographs obtained from three different mice are shown (original magnification × 100). (A) Untransplanted X-CGD mouse. Granulomatous microabscesses are seen, with occasional giant cells. (B) Untransplanted X-CGD mouse. Large inflammatory nodules with a central collection of neutrophils and numerous hyphae are seen. (C) X-CGD mouse transplanted with marrow transduced with the high-titer MSCV-m91Neo retrovirus. Occasional mononuclear cells in perivascular spaces and alveoli are seen, along with macrophages containing colloidal carbon (arrows) that was administered with the conidia to mark the site of delivery.