Figure 1. Neutrophil depleted mice display augmented type 2 inflammation after 3 weeks of HDM exposure.

(A) Balb/c mice were administered HDM or PBS intranasally (i.n.) 3 times per week for up to 3 weeks, and at 24 hours prior to each HDM/PBS administration mice were dosed with either 100 μg of neutrophil depleting antibody, 1A8, or isotype control antibody, 2A3 intraperitoneally (i.p.). At 24 hours, 1 week and 3 week time points (in each instance 24 hours post final HDM/PBS exposure), lung tissue and BALF was collected (Ŧ). Total numbers of neutrophils in the lungs (B) and airways (C) were determined by flow cytometry. (D) Total cell numbers in the lung were assessed after 3 weeks of HDM exposure by trypan blue exclusion. (E) Representative H&E stained lung sections from mice exposed to PBS or HDM for 3 weeks and treated with 2A3 or 1A8. (F) The number of eosinophils in the lung were quantified by flow cytometry at 3 weeks. The number of CD4⁺ T cells expressing T1ST2 (G) or IL-13 (H) in the lung were assessed by flow cytometry after 3 weeks of PBS/HDM exposure. (I) After 3 weeks of HDM/PBS exposure, concentrations of HDM-specific IgE and IgG1 in the serum were determined by ELISA. Figures present combined data from 2 independent experiments with 4-6 mice per group in each experiment. Results depicted as mean ± SEM. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001 using Mann–Whitney statistical test.