Platelet cytoplasmic Ca++ response to eotaxin and TARC alone and in the presence of a blocking antibody directed against CCR3, measured using fura-2 fluorescence.
(A) Plot 1: washed platelets (108/mL) loaded with fura-2 were activated with eotaxin (10 nmol/L) (a), followed by TARC (10 nmol/L) (b) and thrombin (0.1U/mL) (c). Plot 2: eotaxin (10 nmol/L) (d) and TARC (10 nmol/L) were added together. The Ca++ signal is equivalent to that of 0.1 U/mL thrombin in plot 1. (B) Washed platelets (108/mL) loaded with fura-2 were incubated with Fab fragments of anti-CD32 antibodies and then treated with anti-CCR3 antibodies (a) that cause the inhibition of Ca++ signaling by eotaxin (b) but not TARC (c). The results shown are typical of at least 3 similar experiments.
