Antibodies against human granzyme A or B show specificity in recombinant protein competition assays and in knock-out cells. (A) Competition assays with 10-fold molar excess of recombinant granzyme (rGzm) A and/or granzyme B demonstrate anti-granzyme A and B antibody specificities in unstimulated healthy human PBMCs. (B) Anti-granzyme B antibody specificity in wild-type (WT) murine LAKs versus granzyme B knock-out (KO) LAKs. Percentages of total cells for each quadrant are indicated in the upper right corner of each subpanel.