Characterization of Ascaris-induced biphasic skin allergic reaction model in mice: possible roles of mast cells in early-phase and CD4-positive T cells in late-phase reactions.

We established an Ascaris-induced biphasic skin allergic reaction in mice. In the early-phase reaction (EPR), mast cell degranulation was observed, and tranilast inhibited ear edema. In mast-cell-deficient mice (WBB6F(1)-W/W(V) mice), ear edema in the EPR disappeared, whereas that in the late-phase reaction (LPR) remained. Eosinophils increased, and CD4-positive T cells tended to increase in the LPR. Anti-CD4 antibody, anti-IL-4 antibody and anti-IL-5 antibody all inhibited ear edema and had a tendency to inhibit eosinophil infiltration in the LPR. These data suggest that the EPR is induced by histamine released from mast cells, whereas the LPR is induced by IL-4 and IL-5 produced from CD4-positive T cells.