Inhibition of the binding of IgE antibodies in sensitized serum to immobilized rCuc m 2. Inhibition was assayed by a competitive ELISA method. The pooled sera (1: 5 dilution) was preincubated for 1 h with an equal volume of various concentrations from each extraction solution which was made in PBS before adding to the plate coated with rCuc m 2 (50 ng/well). Sample concentrations are expressed as those in preincubation mixture. Inhibition with BSA was used as negative control (not shown).