Table 1.

Detection of cleaved MMAF/E by mass spectrometry

NeutrophilsConditioned medium
Donors1 day6 daysNeutrophilsHSCs
BM33391.2 nmol/L11.5 nmol/L16.8 nmol/L
BM34772.4 nmol/L7.2 nmol/L11.9 nmol/L
  • NOTE: Extracellular cleavage by proteases secreted by differentiating neutrophils. HSCs from two donors (BM3339, BM3477) were differentiated to neutrophils. Differentiating neutrophils at day 8 were incubated with 100 nmol/L AGS5-vcMMAF, and medium was collected after 1 day or 6 days, and free MMAF was measured by mass spectrometry (left side). Neutrophil conditioned medium was collected at day 14. Conditioned medium was also collected from HSCs. Conditioned media from day 14 neutrophils or HSCs were incubated with 100 nmol/L AGS5-vcMMAE for 1 day, and free MMAE was measured by mass spectrometry (right side). “-” indicates below detection limit (0.2 nmol/L).