IL-27 produced by DCs upon infection restricts a cytotoxic phenotype in antiviral CD4 T cells.

<p><i>CD11c</i>^<i>cre+</i><i>IL27p28</i>^<i>fl/fl</i>, <i>LysM</i>^<i>cre+</i><i>IL27p28</i>^<i>fl/fl</i> and cre- littermate controls were infected with 1*10⁴ PFU MCMV and KLRG1 expressing CD11a⁺CD49d⁺ CD4 T cells were analyzed in the blood at day 14 p.i. (A) and in the spleen at day 21 (B) and day 40 (C) p.i. (D-E) GrzA mean fluorescence intensity (MFI) in CD11a⁺CD49d⁺ CD4 T cells from <i>CD11c</i>^<i>cre+</i><i>IL27p28</i>^<i>fl/fl</i> mice (D) and <i>LysM</i>^<i>cre+</i><i>IL27p28</i>^<i>fl/fl</i> (E) compared to cre- littermate controls in the blood at day 14 p.i. (F) <i>Il27p28</i> transcript levels relative to <i>Gapdh</i> in FACS purified CD11b⁺ cDCs (PI^-Thy1.2^-CD19^-NK1.1^-CD138^-CD11c^hiB220^-CD11b⁺CD8^-), CD8⁺ cDCs (PI^-Thy1.2^-CD19^-NK1.1^-CD138^-CD11c^hiB220^-CD11b^-CD8⁺), and pDCs (PI^-Thy1.2^-CD19^-NK1.1^-CD138^-CD11c^dimCD11b^-B220⁺PDCA⁺) from spleens of WT mice 36 hours post MCMV infection compared to uninfected controls. (A-E) representative of two independent experiments with n = 5 mice per group. (F) One independent experiments with pooled samples from n = 5 mice per group. * p < 0.05.