Fig. 4.

miR-29a promotes memory-like CD8 T cell responses in chronic infection. (A and B) CD45.1⁺ P14 CD8 T cells were transduced with either control empty-VEX RV (ctrl) or miR-29a OE-VEX RV (miR) and adoptively transferred as shown in Fig. 2A. (A) Percentages of terminal effector and memory precursor P14 cells (gated on VEX⁺ P14 cells) at d30 p.i. (B) Intracellular expression of TCF-1 and surface Ly108 at d30 p.i. (C–F) At d34 p.i., transduced VEX⁺ and nontransduced VEX- P14 cells were sorted from the spleens of donor mice. A total of 50,000 sorted VEX⁺ or VEX⁻ P14 cells were separately adoptively transferred to congenic recipient mice that were infected with LCMV V35A at 35 d prior. Recipient mice were then challenged with influenza virus PR8-gp33 2 d later. (D) Secondary expansion of transferred P14 cells was analyzed on 9 d after PR8-gp33 infection. (E and F) The phenotype of transferred P14 cells was analyzed on d9 after PR8-gp33 infection. Fluorescence-activated cell-sorting plots are gated on CD45.1⁺ P14 cells. mLN, mediastinal lymph nodes.