(A) The generation of monoclonal therapeutics on difference constant domain isotypes can drive significantly different functions, and (B) induce hierarchically different levels of tumor mediated killing in the presence of NK cells. (C) Similarly, simply altering the glycan structure attached to the same antibody heavy chain car lead to different antibody effector functions, (D) where the removal of a single sugar, fucose, has been shown to improve NK cell mediated tumor clearance dramatically.