Figure 5. Bone marrow chimera experiments demonstrate that NADPH oxidase in hematopoietic cells, but not lung stromal cells, is required to restrain zymosan-induced lung inflammation.

Wild type (WT) and p47^phox−/− (CGD) mice were administered myeloablative total body irradiation, and rescued with marrow-derived WT or p47^phox−/− donor cells. The transplants were as follows: WT donor/CGD recipient (n = 3); CGD donor/WT recipient (n = 3); WT donor/WT recipient (n = 2); CGD donor/CGD recipient (n = 2); the latter two transplants were performed as specificity controls for artifacts introduced by transplantation. Recipient mice were administered i.t. zymosan at 31 days after transplant. Seven days later, peripheral blood and lungs were harvested. A) NADPH oxidase activity in peripheral neutrophils of transplanted mice was evaluated using the fluorescent probe, dihydrorhodamine 123 (DHR). In a representative experiment, neutrophils were unstimulated (top row) or stimulated with PMA (100 ng/ml) (bottom row) to activate NADPH oxidase. Hydrogen peroxide, a metabolite of NADPH oxidase activation, activates DHR fluorescence. In all transplants, the donor genotype determined NADPH oxidase competence. B) Representative lung histology (H&E, 40x) and C) percent of lung parenchyma with consolidation or granulomatous inflammation in transplanted mice at day 7 after i.t. zymosan administration. Percent lung inflammation was significantly greater in transplanted mice with CGD compared to wildtype donors (abbreviated, “D” in the figure) (unpaired t-test, p<0.0001), whereas recipient (abbreviated, “R” in the figure) genotype had no effect on the inflammatory response.