Flow cytometric analysis of mononuclear cells after anti-CD137 mAb treatment. Naive B6 mice (Thy1.2) were transferred with 10⁷ purified activated (A) or naive (B) OT-1 T cells (CD8⁺ Thy1.1). As previously described, 3 weeks later they were treated with rat Ig or anti-CD137 mAb. At 10 days after antibody treatment, mononuclear cells were harvested from spleen, lymph nodes (axilla and inguinal), and peripheral blood. OT-1 T cells were identified by anti-Thy1.1 mAb. Absolute numbers of OT-1 T cells of spleen, lymph nodes, and peripheral blood were calculated. Subsets of effector Tms (CD44^hiCD62L^lo), central Tms (CD44^hiCD62L^hi), and naive T cells (CD44^lo) of OT-1 T cells were identified by the indicated specific mAbs. Results are 1 representative of at least 3 independent experiments. ns indicates not significant; *P < .05; ***P < .005.