CD43 has an antiapoptotic function. (A) PI and annexin V staining of Gr-1⁺ cells purified from bone marrow cells of wt and CD43-deficient mice after 36-hour culture in RPMI without growth factors. (B) Data show percentage of live and nonapoptotic cells (PI⁻/annexin V⁻) in cultures of wt (■) and CD43-deficient (▩) cells; Gr-1⁺ cells purified from bone marrow (BM), B220⁺ cells purified from bone marrow and from spleen (SP), CD4⁺/CD8⁺ T cells purified from spleen, and macrophages (Mφ) cultured from bone marrow cells. Data for Gr-1⁺ and Mφ cells are shown after a 36-hour time point; B220⁺ and CD4/CD8⁺ cells are shown after a 16-hour time point, n = 3. (C) Purified CD4⁺ T cells from wt (dashed line) and CD43-deficient (solid line) mice were stained with CFSE and stimulated with ConA. FACS profiles show CFSE dilution, PI, and annexin V profiles of cultures without Treg (top panels) and with 30 000 Treg added (bottom panels) 3 days after mitogen stimulation. (D) Naive T cells maintained in RPMI without growth factors were treated with γ-secretase inhibitor (▩; L685,458) or vehicle control (■; No treatment). Induction of apoptosis was assessed by determination of caspase-3 activity or annexin V and PI staining 2 hours and 16 hours after initiation of culture conditions, respectively. n = 3; *P < .05 and **P < .01 (Student t test). Data are mean ± SD and are representative of at least 3 independent experiments.