Figure 10.

Forced retroviral expression of Eomes in vivo restores CD8⁺ memory generation in the absence of N-ras. N-ras^+/+ or N-ras^−/− OT-I CD45.1^+/+ splenocytes were stimulated with OVA peptide in vitro for 24 h, CD8⁺ T cells purified, transduced with control GFP-expressing (MigR1), or with GFP-Eomes-expressing retroviruses and separately injected into naive CD45.1^−/− CD45.2^+/+ N-ras^+/+ recipient mice that were infected concurrently or 14 d later with rVACV-OVA. On day 8 after primary exposure to antigen, and on day 5 after secondary infection, CD8⁺ PEC and splenocytes were analyzed by flow cytometry, as indicated. Representative dot plots of PEC (A) as well as graphs representing four individual mice in each group (B) of retrovirus-transduced (GFP⁺) and transferred (CD45.1⁺) CD8⁺ lymphocytes from PEC and spleen during the primary and secondary response, as indicated, are depicted. In A, numbers refer to percentage cells with respect to all CD8⁺ T lymphocytes, including GFP⁻ CD45.1⁻ endogenous CD8⁺ T cells. In B, numbers represent the percentage of GFP⁺ transduced cells with respect to total CD45.1⁺ transferred CD8⁺ T cells, excluding endogenous CD8⁺ T cells; horizontal bars show the mean values. A representative experiment out of two is shown. ***, P < 0.0005.