PMC

Reciprocal modulation of C3aR and C5aR expression in pulmonary dendritic cells after HDM exposure. A, Relative expression of C3aR mRNA in pulmonary CD11c⁺ dendritic cells from BALB/c WT and C5aRKOs (upper panel). Fold increase of C3aR mRNA expression in HDM-treated group relative to PBS-treated group (lower panel). B, Relative expression of C5aR mRNA in pulmonary CD11c⁺ dendritic cells from BALB/c WT and C3aRKOs (upper panel). Fold decrease of C5aR mRNA expression in HDM-treated group relative to PBS-treated group (lower panel). Values shown are the mean ± SEM. n = 10 –25 per group.

C5aR targeting in C3aRKOs reverts the impaired Th2 immune responses. A, Airway responsiveness to i.v. acetylcholine. B, Total and eosinophil cell counts in BAL. C, Cytokine profile of pulmonary cells harvested from mice 72 h after the final in vivo HDM exposure. D, Serum concentrations of total IgE and HDM-specific IgE. Values shown are the mean ± SEM; n = 5–15 per group.

Protocols underlying the mouse model of HDM-induced experimental allergic asthma. A, Mice were exposed to i.t. HDM at the indicated time points. Seventy-two hours after the final HDM exposure, airway responsiveness was determined. Subsequently BAL, lung cells, and blood samples were collected. B, To block C5aR signaling, mice were treated with the anti-C5aR mAb i.t. 24 h before each HDM exposure on days –1, 6, 13, and 20. C, Pulmonary DCs and T cells were isolated and cocultured 16 h after the final HDM exposure. The expression of costimulatory molecules on pulmonary DCs was also measured.

The lack of C3aR or C5aR signaling has opposing effects on the development of the allergic phenotype in response to pulmonary HDM exposure. A, Airway responsiveness to i.v. acetylcholine. Airway responsiveness is expressed as the time-integrated change in airway pressure over baseline pressure. B, Total and eosinophil cell counts in BAL. C, Cytokine profile of pulmonary cells harvested from mice 72 h after the final in vivo HDM exposure. Supernatants were collected after 72 h in vitro cell culture. D, Serum concentrations of total IgE and HDM-specific IgE. Values shown are the mean ± SEM. n = 10 –25 per group. APTI, airway pressure time index.

C5aR targeting during allergen sensitization regulates Th2 cytokine production through its impact on the expression of B7-H1 and B7-DC costimulatory molecules on pulmonary pDCs. A, Expression of B7 costimulatory molecules on pulmonary mDCs (upper panel) and pulmonary pDCs (lower panel) isolated from mice 16 h after the final in vivo HDM exposure. B, Cytokine levels in supernatants of pulmonary CD11c⁺ DC and CD4⁺ T cell cocultures. Pulmonary CD11c⁺ DCs were isolated and incubated in vitro with specific neutralizing anti-B7-H1 or anti-B7-DC Abs for 2 h. DCs were then cocultured with pulmonary CD4⁺ T cells for 72 h before cytokine levels were measured. All groups were subjected to in vivo HDM treatment. The y-axes shows the fold increase in cytokine levels as compared with in vitro PBS controls. Values shown are the mean ± SEM. n = 10 –25 per group. ±, p < 0.05; 33, p < 0.01; 333, p < 0.001.