Fig. 3.

Compromised mitogenic and homeostatic proliferation of TPPII-deficient CD8⁺ T cells. (A–C) Mitogenic responses to anti-CD3 and IL-2 in vitro. (A) Reduced recovery of viable cells after stimulation of purified CD8⁺, but not CD4⁺, splenocytes. (B) Left to right, staining of WT and TPPII KO splenocytes with anti-CD3 ex vivo, with anti-CD69 after 24 h of stimulation, viable cells by FCS/SSC, and numbers of cell divisions by loss of CFSE after 5 days of stimulation. (C) Staining with annexin V after 48 h of in vitro stimulation of CD8 T cells. (D) Reduced numbers of proliferating CD8⁺, but not CD4⁺, KO T cells after adoptive transfer into sublethally irradiated B6 mice. Histograms show representative CFSE profiles of CD8⁺ or CD4⁺ lymph node cells at day 4 and day 7, respectively. Peak designation: u, undivided cells; 1, 2, 3, and 4, peaks containing cells that have undergone one to four cell divisions. (E) Apoptosis of homeostatically proliferating T cells. Determined was the percentage of annexin V-positive dividing cells. Cells that were gated are indicated by the brackets in D. Data are representative of experiments done at least three times independently, and data in A and C are representative of at least 10 experiments.