Generation and characterization of BaF3/PAR-2 cells. Mock-transfected (BaF3 cells) or BaF3/PAR-2 cells were plated into 96-well clusters (2 × 10⁴ cells/well) and incubated in complete media (RPMI, 10% fetal calf serum) with (WEHI⁺) or without (WEHI⁻) 10% WEHI supernatant (as the exogenous source of IL-3), or 100 μmol/L PAR^39-44 for 48 hours, before proliferative assays using MTT essentially as outlined in the Materials and Methods. Only BaF3/PAR-2 cells showed proliferative responses to PAR-2 peptidomimetics. No responses were seen using the inactive peptide LSIGRL (not shown). All points represent the mean ± the standard error of the mean (SEM) of four wells from a single representative set of experiments.