Peak activation of NK cells. The percentage of NK cells activated (as indicated by CD54_bright expression) was identified for each mAb at peak activation irrespective of mAb concentration. Peak CD54 activation for AME-B or AME-D is compared with that of R. NK cell activation by mAb-coated target cells was greater for AME-D than for AME-B or R in each sample tested. (Top) AME-B versus rituximab. (Bottom) AME-D versus rituximab.