Anti-CD37 ATACs induce apoptosis in vitro and prolong survival of RS-PDX mice. (A) The apoptotic response of RS cells exposed for 72 hours to different doses (40 and 200 nM) of anti-CD37-Ama 1, anti-CD37-Ama 2, and anti-CD37-Ama 3 or left untreated was analyzed with conventional cytofluorimetric annexin V/PI staining (n = 5 per model; box and whiskers, minimum to maximum representation). (B) RS cells were injected IV into NOD/SCID/γ chain^−/− mice and left to engraft (Eng) for 2 weeks. The mice were then randomly assigned to different treatment groups (4 mice per group). After anti-CD37 ATAC administration (Tx), mice were monitored (W&W, watch and wait) and survival analyses performed, generating Kaplan-Mayer curves. (A) Asterisks on the box plots refer to statistical significance vs the untreated condition; P values with bars refer to the indicated conditions. Statistical analyses were performed with the paired t test. *P < .05; **P < .01; ***P < .001.