Figure 1. Arg1 expression by macrophages does not regulate acute schistosome egg-induced pulmonary granuloma formation and Th2 response.

Mice deficient in Arg1, iNOS, or both enzymes were sensitized by i.p. injection of eggs, then challenged by a single i.v. injection of eggs to form pulmonary granulomas and analyzed at 2 weeks. A) T lymphocytes (CD3+), macrophages (F4/80+), and Arginase1+ cells were detected in fixed lung serial sections using immunohistochemistry. Images represent 8 mice of each genotype. B) The volume and eosinophil composition of 10–30 granulomas per mouse were scored in Geimsa-stained lung sections. C) Collagen deposition was compared by measuring L-hydroxyproline in matched lobes and calculating, by mass, total lung content. D) Expression of Arginase 2 or E) IL-13 mRNA and the Th2-responsive genes RELM-α, Mucin 5AC, and Gob5 were compared in lung tissue by quantitative PCR, normalized to the mean naïve WT level. F) To evaluate CD4 T cell responses, lung leukocytes were restimulated with PMA plus ionomycin and stained to detect IL-13, IL-4, IL-5, and IFN-γ by flow cytometry. No significant differences were observed between the challenged groups in B) to F). Results were combined from two independent experiments totaling 11 to 19 mice per group, plus 6 naïve WT controls. Individual mice and group means are shown.