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Figure S1. Phenotypic and functional characterization of Bmi1^−/− Th2 cells. (A) Naive CD4 T cells were labeled with CFSE, and the cell division was determined at the 48-h time point after stimulation with antigenic peptide and APC. The numbers of cell divisions of the cells are also shown. Note that the cell division was not decreased but rather slightly increased in Bmi1^−/− cells. (B) Expression profiles of cell surface maker antigens on Bmi1^−/− memory Th2 cells. Spleen cells of memory Th2 mice were stained with KJ1 mAb and mAbs against indicated cell surface molecules. Cell surface expression profiles of electronically gated KJ1⁺ cells are shown. (C) Responses to the antigenic peptide in memory Th2 cells. Bmi1^+/+ and Bmi1^−/− KJ1⁺ cells were isolated from the spleens of memory Th2 mice and stimulated with antigenic peptide plus APCs for 24 h in vitro. The apoptotic cells in the KJ1⁺ memory Th2 cells were determined by the staining with annexin V and PI.