Surface expression of B1Rs and B2Rs on IMR-90 cells. IMR-90 cells were incubated for 6 hours with either 10 μM BK, 10 μM desArg⁹BK, 500 pg/mL IL-1β, 1% (vol/vol) PBMC exudates (supernatants of monocytes that had been stimulated for 24 hours with 1% S aureus overnight culture supernatants), 1% PBMC exudates in the presence of 10 μM BK, 1% PBMC exudates in the presence of 10 μM desArg⁹BK, or media alone in the absence of serum. After a washing step, cells were assayed for specific [³H]Des-Arg¹⁰kallidin (B1R ligand) binding (A) and [³H]BK (B2R ligand) binding (B). Binding of [³H]Des-Arg¹⁰kallidin and [³H]BK to nonstimulated cells (control) was normalized to 100% within each experiment. Results represent the mean ± SEM of 3 independent experiments performed in triplicate. **P < .01 by analysis of variance followed by Tukey method for pairwise comparisons.