Figure 3.

Diverse cell fates associated with KLRG-1^Int and KLRG-1^Hi effector CD8 T cells are independent of initial precursor frequencies of antigen-specific cells and are seen with both Tg T cells and endogenous cells in normal B6 mice. (A) B6 mice adoptively transferred with low (10³) or high (10⁵ or 10⁶) doses of naive P14 cells were infected with LCMV. CD8⁺ Thy1.1⁺ donor cells in the spleen were analyzed for cell-surface KLRG-1 expression at days 4, 5, and 6 p.i. Vertical red lines indicate the gate for intermediate KLRG-1 expression. (B) KLRG-1^Int and KLRG-1^Hi effector cells were sorted from B6 mice containing 10⁶, 10⁵, or 10³ naive P14 cells at days 4, 4.5, and 6 p.i., respectively. KLRG-1^Int and KLRG-1^Hi donors from each group were transferred into infection-matched recipients, and total numbers of memory cells in the spleen were enumerated at days 40–60 after transfer. Mean data are plotted, and error bars represent SEM. (C) Non-Tg B6 mice were infected with LCMV, and 6-d p.i. cell-surface expression of KLRG-1 on D^bGP33-, D^bNP396-, and D^bGP276-specific CD8 T cells was assessed using anti-CD8α, anti–KLRG-1, and the respective MHC class I tetramers. Numbers show the frequency of tetramer-positive cells. (D) Tetramer-specific cells were sorted into KLRG-1^Int and KLRG-1^Hi populations from Thy1.2⁺ B6 mice infected with LCMV 6 d earlier. A total of 1.5 × 10⁶ KLRG-1^Hi– and KLRG-1^Int–sorted D^bGP33⁺ D^bNP396⁺ D^bGP276⁺ cells were transferred into infection-matched Thy1.1 recipients. Total numbers of D^bGP33⁺ D^bNP396⁺ D^bGP276⁺ donor cells in the spleen are shown at 20 d after transfer. (E) Surface markers were analyzed on D^bGP33-specific CD8 T cells by direct ex vivo staining of splenocytes, and production of IL-2 by memory cells was determined by ex vivo stimulation with GP33 peptide for 5 h. Bar graphs represent the fraction of donor cells expressing the indicated markers. Mean data are plotted, and error bars represent SEM.