Changes in cytosolic free calcium in response to HrHRF or a known positive stimulus, PAF.

Eosinophils were preincubated with either the inactive β-oligomer of PT (panels A,B) or PT (panels C,D) and loaded with Fura 2-AM. Cells were then stimulated (arrows) with 0.7 μmol/L HrHRF (panels A,C) or 1 μmol/L PAF (panels B,D). The average calcium response ± SEM (vertical bars) of eosinophils from 4 donors is expressed as the relative change in Fura 2-AM saturation. P values indicate differences between 8 time points before and after the addition of stimulus.