2.12. Passive cutaneous anaphylaxis (PCA)
C57BL/6 mice (6-8 week old) were locally sensitized with an intradermal
injection of anti-DNP-specific IgE (100 ng/ear) into the right ear
followed 24 h later by topical treatment with sophoricoside (3 or 30
mg/kg). Control mice were injected with the same volume of PBS and
topically treated with 0.1% DMSO. One hour later, the mice were
intravenously challenged with soluble antigen (100 µg DNP-HSA) in 100 µL
PBS containing 5% Evans blue dye. One hour after antigen challenge, the
dye was extracted from each dissected ear in 0.8 mL formamide at 65°C
for overnight. The amount of extracted dye was measured
spectrophotometrically at 620 nm and calculated from a standard curve
established with known amounts of dye.