TLR ligands do not affect degranulation and release of [¹⁴C]arachidonic acid. IgE-primed MC/9 cells and BMMCs were exposed to vehicle (NS), antigen (Ag; 20 ng/mL), PGN (100 μg/mL), P3C (1 μg/mL), LPS (100 ng/mL), or MALP2 (100 μg/mL) (A-B) or with the indicated concentrations of Ag or P3C plus 1 μg/mL P3C (C) or 20 ng/mL Ag (D) for 20 minutes for measurement of released β-hexosaminidase. (C-F) Vehicle was substituted for antigen in the samples designated “0.” Virtually identical results were obtained with LPS (100 ng/mL), PGN (100 μg/mL), and MALP-2 (100 ng/mL) as those shown in panel C (data not shown). For measurement of production of [¹⁴C]arachidonic acid, cells were incubated with [¹⁴C]arachidonic acid (1 μCi/mL [0.037 MBq]) for 18 hours before stimulation with antigen in combination with P3C (1 μg/mL) for 20 minutes (E,F). Values are the mean ± SEM from 4 experiments and are expressed as percent release of intracellular β-hexosaminidase or as a percent of total intracellular [¹⁴C]lipids that were released into the medium as [¹⁴C]arachidonic acid.