Natural Killer Cell-Mediated L

cytotoxic lymphocyte activity can result in disease. In cytotoxic lymphocyte function. Both inhibitors were de-some cases, the granzymes may thus represent poten- signed to have the general architecture of tagged affin-tial therapeutic targets [3–7]. ity labels. This design allowed for rapid evaluation of Granzymes A and B are the most prominent mem- selectivity in the context of NK and target cell pro-bers of the granzyme family, as numerous experiments teomes by SDS-PAGE analysis, followed by detection have implicated them in the induction of target cell of a biotin label. Each inhibitor was found to be ex-death. Notably, mice lacking either or both of these tremely selective for its target enzyme in the context of complex biochemical mixtures. The granzyme A- and B-targeted inhibitors were thus used to probe the con-*Correspondence