HGS-ETR1 and HGS-ETR2 mAbs kill HMCLs. HMCLs (125 000 cells/0.25 mL in a 96-well plate) were treated for 48 hours with 0.06, 0.6, and 6 μg/mL HGS-ETR1 (□) or HGS-ETR2 (○) mAbs. HMCLs were cultured with or without 3 ng/mL IL-6 (see “Materials and methods”). Percentages of dead cells were determined as described in “Materials and methods.” Results are representative of at least 1 of 3 experiments (Table 1).