Induction of ear swelling (A), mast cell activation (B), and IL-6 mRNA expression (C and D) by ID injection of rrSCF (30 μg/kg/site), LPS (13 pg/kg/site), or vehicle alone in the ear skin of C57BL/6 mice (n = 5 to 10 per treatment group). (A) Ear swelling measured 2 hours after injection of rrSCF into the left ears or LPS alone (in the same amount as was present in the rrSCF solution) into the right ears or 2 hours after injection of LPS into the left ears and vehicle alone into the right ears. *P ≤ .001 versus values for LPS-injected or vehicle-injected ears. (B) Extent of mast cell activation in the rrSCF-, LPS-, or vehicle-injected ear skin. *P < .0001 versus LPS- or vehicle-injected ears. The differences between values for LPS- or vehicle-injected ears (in A or B) are not statistically significant (P < .1).