Mast cell degranulation

Mast cells obtained from the PEC of NSG-SGM3 BLT mice were cultured in the presence of chIgE-anti-NP overnight at indicated concentrations. The following day 50 ng/mL NP-BSA (Bioresearch Technologies) was added for 30 minutes at 37°C to crosslink IgE and initiate mast cell degranulation. Culture supernatants were assayed for β-hexosaminidase (β-hex) release for 1.5 hours at 37°C in β-hex substrate solution containing 4-Nitrophenyl N-acetyl-β-D-glucosaminide in 0.09M citrate buffer at pH 4.5. Release of 4-Nitrophenol was monitored at 405 nM.