Figure 1.
Experimental protocols for chronic exposure to house dust mite (HDM).
(A) Mice received intranasal HDM on 4 consecutive days per week for 5 consecutive weeks with concomitant administration of anti-IL-13 mAb, isotype control or vehicle s.c. weekly (prophylactic treatment). (B) Mice received intranasal HDM on 4 consecutive days per week for 8 consecutive weeks with concomitant administration of anti-IL-13 mAb, isotype control or vehicle s.c. weekly starting on week 6 (therapeutic treatment). AHR and baseline lung function was assessed as RL and Cdyn in terminally anaesthetised mice 24 hours after the last HDM instillation on day 32 (A) or day 53 (B). BAL and lungs were removed on day 32 (A) or day 53 (B) for assessment of airway inflammation and histological analysis. In addition, lungs were taken from an additional group on day 35 for histological analysis prior to therapeutic treatment (week 5 lungs, B).
Figure 2.
Up regulation of IL-13 in HDM sensitised mice.
(A) IL-13 concentration in lung homogenate after 5 weeks of HDM sensitisation. (B) IL-13 mRNA expression in lung tissue relative to saline sensitised mice. Data are shown as mean ± SEM, n = 8 mice per group. ** p<0.01, *** p<0.001 relative to saline group by unpaired t test.
Figure 3.
Effect of IL-13 neutralisation on BAL leukocytes.
(A–E) Mice were treated prophylactically with anti-IL-13 mAb (10 mg/kg, s.c., weekly) administered immediately prior to and throughout HDM exposure. (F–J) Effect of IL-13 neutralisation on established airway inflammation. Mice were exposed to HDM for 8 consecutive weeks and treated with anti-IL-13 mAb therapeutically (10 mg/kg, s.c., weekly from week 6). Data are shown as mean ± SEM, n = 8 mice per group. *p<0.05, ** p<0.01, *** p<0.001 relative to HDM group by one-way ANOVA followed by Dunnett's post test.
Figure 4.
Effect of IL-13 neutralisation on epithelial goblet cell upregulation.
(A–C) Representative photomicrographs of airway sections stained with AB/PAS (original magnification ×200) from mice exposed for 5 weeks to saline (A) or HDM (B–C) and treated prophylactically with vehicle (B) or anti-IL-13 mAb (C) (10 mg/kg s.c., weekly) immediately prior to and throughout HDM exposure. (D) Mice were treated prophylactically with anti-IL-13 mAb (10 mg/kg, s.c., weekly) administered immediately prior to and throughout the 5 consecutive weeks of exposure to HDM. (E) Effect of anti-IL-13 neutralisation on established goblet cell upregulation. Mice were exposed to HDM for 8 consecutive weeks and treated therapeutically with anti-IL-13 mAb (10 mg/kg, s.c., weekly from week 6) Week 5 HDM mice represent lung pathology immediately prior to therapeutic treatment, after 5 weeks of HDM exposure. Data are shown as mean ± SEM. n = 9–10 mice per group. *** p<0.001 relative to HDM group by one-way ANOVA followed by Dunnett's post test.
Figure 5.
Effect of IL-13 neutralisation on peribronchial collagen thickness.
(A–C) Representative photomicrographs of airway sections stained with Masson's trichrome (original magnification ×200) from mice exposed for 5 weeks to saline (A) or HDM (B–C) and treated prophylactically with vehicle (B) or anti-IL-13 mAb (10 mg/kg s.c., weekly) (C) immediately prior to and throughout HDM exposure. (D) Mice were treated prophylactically with anti-IL-13 mAb (10 mg/kg, s.c., weekly) administered immediately prior to and throughout the 5 consecutive weeks of exposure to HDM. (E) Effect of anti-IL-13 neutralisation in mice with an established increase in collagen thickness. Mice were exposed to HDM for 8 consecutive weeks and treated therapeutically with anti-IL-13 mAb (10 mg/kg, s.c., weekly from week 6). Week 5 HDM mice represent lung pathology immediately prior to therapeutic treatment, after 5 weeks of HDM exposure. Data are shown as mean ± SEM. n = 9–10 mice per group. * p<0.05, *** p<0.001 relative to HDM group by one-way ANOVA followed by Dunnett's post test.
Figure 6.
Effect of IL-13 neutralisation on lung function and AHR to inhaled MCh.
AHR to MCh was determined as changes in lung resistance (RL) and dynamic compliance (Cdyn) measured after 5 weeks (A–D) or 8 weeks (E–H) of exposure to HDM. (A–D) Mice were treated prophylactically with anti-IL-13 mAb (10 mg/kg, s.c., weekly) or isotype control administered immediately prior to and throughout the 5 consecutive weeks of exposure to HDM. (A, B) Baseline RL and Cdyn were determined prior to MCh exposure. (C, D) Changes in RL and Cdyn in response to MCh relative to PBS response. (E–H) Mice were exposed to HDM for 8 consecutive weeks and treated therapeutically with anti-IL-13 mAb or isotype control from week 6 (10 mg/kg, s.c., weekly). (E, F) Baseline RL and Cdyn were determined prior to MCh exposure. (G, H) Changes in RL and Cdyn in response to MCh relative to PBS response. Data are shown as mean ± SEM. n = 7–8 mice per group. * p<0.05, ** p<0.01, *** p<0.001 relative to HDM group by one-way ANOVA followed by Dunnett's post test.