FIGURE 6.

A1-knockdown mice exhibit markedly reduced IgE-dependent cutaneous PCA. (A) WT mice (n = 6), VVFF mice (n = 7), and VVA1 mice (n = 5) were sensitized passively by intradermal injection of 20 ng of DNP-specific IgE (SPE-7) and then challenged by i.v. injection the next day with 200 μg of DNP. Ear swelling was measured immediately before and at 30-min intervals after Ag challenge for 6 h. **p < 0.01, ***p < 0.001, versus WT and VVFF mice, two-way ANOVA with Bonferroni correction for multiple comparisons. The data shown were pooled from three independent experiments, each of which gave similar results. (B) Numbers of mast cells in the dermis of ear pinnae at sites of PCA 6 h after DNP challenge. ***p < 0.001, versus WT and VVFF mice, Student t test. (C) Representative toluidine blue staining of activated mast cells in ear pinnae 6 h after induction of a PCA reaction. Arrows indicate mast cells.