(A–D) WT B6 and B6-Reg3g^–/– (KO) mice (Lgr5-EGFP⁺) received PBS or IL-22 injections from day +1 after BMT from B6-Ly5.1 donors (GVHD –) or C3H.SW donors (GVHD +). On day +7 after BMT, small intestine crypt cells were analyzed by flow cytometry, and Reg3g mRNA was measured by qPCR. (A) Quantification of ISCs from mice in Figure 7. (B) Quantification of ISCs undergoing early apoptosis by annexin V⁺ staining in the mice from Figure 7. Data are combined from 3 separate experiments. (C) Quantification of EdU⁺ ISCs in syngeneic recipients (GVHD –: WT-PBS, empty black circles, n = 7; WT–IL-22, empty blue circles, n = 4; KO-PBS, empty red squares, n = 9; KO–IL-22, empty blue squares, n = 5), allogeneic recipients (GVHD +: WT-PBS, filled black circles, n = 8; WT–IL-22, filled blue circles, n = 9; KO-PBS, filled red squares, n = 13; KO–IL-22, filled blue squares, n = 11), and naive WT (downward triangles, n = 5) and KO (upward triangles, n = 5) controls. (D) Correlation of ISCs and Reg3g mRNA expression in WT mice from 2 of the 3 experiments shown in A (n = 25), as calculated by the Pearson correlation coefficient. (E–G) HT-29 cells were cultured with recombinant REG3α protein and apoptotic stimuli as described in Methods. Data are representative of 3 independent experiments. (E and F) Cell lysates were collected after 16-hour cell culture for Western blot analysis. Quantification of cleaved caspase-3 (E) and cleaved caspase-8 (F) expression. (G) Quantification of cell viability by CellTiter-Glo 2.0 assay after 24-hour cell culture. *P < 0.05, **P < 0.01, unpaired 2-tailed t test. Data are expressed as mean ± SEM. ND, not detectable.