<i>L. monocytogenes infection primes cytokine expression in Tpl2-defecient CTLs</i>.

<p>(A) Total CD8⁺ T cells were isolated from Tpl2^+/+ (n = 4) and Tpl2^−/− (n = 4) mice, which carried the CD45.2 congenic marker. Isolated cells from each mouse were separately injected into three CD45.1 recipient mice at 1e⁶ cells per mouse, intravenously on day -1. On day 0 mice were either infected with 2000 CFU of LM-OVA or left uninfected. Spleens were harvested day 7 post infection and splenocytes were cultured with SIINFEKL (10 nM), HKLM (5 mg/mL), soluble anti-CD3 (0.5 μg/mL), or left unstimulated for 18 h. Monensin was added to the cultures for the last 6 h. Intracellular expression of IFN-γ and TNF-α were measured by flow cytometry along with the surface markers CD8a and CD45.2. (B) Intracellular IFN-γ (x-axis) and TNF-α (y-axis) expression after 2° stimulation is represented in dot plots for both Tpl2^+/+ and Tpl2^−/− mice. Transferred cells were identified based on positive staining for CD8α and CD45.2 surface marker. (C–D) Total IFN-γ (C) and TNF-α (D) expressing cells were quantified as a percentage of the identified total transferred (CD8⁺CD45.2⁺) T cells. Mean±SEM is plotted representing triplicate donor mice with Tpl2^+/+ in black and Tpl2^−/− in white bars. No statistically significant differences in cytokine expression were observed between strains as assessed by two-way ANOVA.