Allogeneic cytotoxicity of granzyme B^−/− × gld/gld CTLs against three different tumor cell lines. H-2^b anti–H-2^d CTLs produced in day 5 MCR cultures from granzyme B^+/+ (B^+/+), granzyme B^−/− (B^−/−), and granzyme B^−/− × gld/gld (B^−/− × g/g) spleens were tested against TA3 (A and B), P815 (C and D), and YAC-1 (E and F) cells at varying E:T ratios after 10 hours of incubation in a ⁵¹Cr release (A, C, and E) and ¹²⁵IUdR release (B, D, and F) assays. All three types of effector cells induce similar levels of ⁵¹Cr release from TA3, P815, or YAC-1 targets. Granzyme B^−/− × gld/gld CTLs exhibit reduced amounts of ¹²⁵I-labeled DNA release at all E:T ratios tested against all three lines.