Figure 7.

Suppression of CS-induced neutrophilia by hematopoietic and non-hematopoietic AhR expression. (A) Schematic of bone marrow chimeras: AhR-KO mice (recipient) were irradiated with 9 Gy and bone marrow cells transferred from Ahr-expressing (Ahr^Ahr) mice to create chimeric mice in which the non-hematopoietic (structural) cells are KO but hematopoietic cells have AhR. Control mice (after irradiation of recipient) included Ahr^Ahr (all cells with AhR) and Ahr-KO^KO (all cells KO). (B) Flow cytometry of CD45.1 cells: Bone marrow cell subsets from Ahr-KO^KO (CD45.2) and BM chimeric mice Ahr-KO^Ahr (CD45.1) were labeled with antibodies for CD45.1 and CD45.2 and analyzed using flow cytometry. Data presented are representative dot plot. For the Ahr-KO^Ahr mice, BM cells were entirely donor derived (CD45.1) after reconstitution. (C) BAL neutrophils: acute (3 day) CS exposure significantly increased BAL neutrophils in Ahr^Ahr mice, Ahr-KO^KO, and chimeric (Ahr-KO^Ahr) mice compared to respective air-exposed mice (***p < 0.001). Neutrophils were significantly higher in Ahr-KO^KO (**p < 0.01) and Ahr-KO^Ahr mice (**p < 0.01) compared to Ahr^Ahr mice. There was some reduction in neutrophils in Ahr-KO^Ahr mice. N = 4–5 male mice per experimental condition.