Loss of Ezh2 impairs the survival and expansion of alloantigen-activated T cells during the later stages of GVHD induction. Donor CD44^lo T cells derived from B6/SJL WT (H2^b) or B6 T-KO (H2^b) mice were labeled with CFSE and transplanted with TCD BM into irradiated BALB/C recipients (H2^d) (A-C). Seven days later, donor T cells were recovered for analysis. (A) Dot plots show the fraction of donor-derived CD4⁺ T cells, and histograms show their CFSE dilution. Graphs show the number of donor T cells. (B) Histograms and graphs show Annexin V⁺ CD4⁺ T cells. (C) Graphs show the number of donor-derived CD4⁺ T cells in different organs. (D) CD44^lo T cells (CD4⁺ T cells) derived from WT or T-KO B6 mice were stimulated by BALB/C BM-derived DCs. Five days later, cells were collected for BrdU assay. (E) B6 (H2^b) WT or T-KO T cells (CD4⁺ + CD8⁺ T cells) were transplanted into nonirradiated BDF1 (H2^b/d) mice. Seven days later, cells were recovered for analysis. Histograms and graphs show the CFSE dilution and number of donor T cells. (F-G) A homeostatic proliferation assay was performed by transferring B6/SJL WT T cells (CD45.1) and B6 T-KO T cells (CD45.2) into lethally irradiated syngeneic B6xB6/SJL (CD45.1/CD45.2) recipients. (F) Dot plots show the fraction of donor-derived CD4⁺ T cells, and histograms show their CFSE dilution. (G) Histograms and graphs show Annexin V⁺ in donor CD8⁺ T cells. Data shown are representative of 2 independent experiments, each with 3 to 5 mice per group. *P < .05, **P < .01, ***P < .001. Error bars indicate mean ± SD.