Effector-memory Maxi CD8 T cells are maintained in lungs independently of antigen and have longer half-lives than effector Maxi CD8 T cells.

<p>(A) Naïve Maxi CD8 T cells were adoptively transferred into naïve C57BL/6 mice followed by i. v. MCMVΔm157 infection. Effector-memory Maxi CD8 T cells were sorted from the lungs and transferred into infection-matched or naïve recipients. Total numbers of Maxi cells were assessed in the lungs at <1, 6 and 12 weeks post transfer. (B) Representative contour plots showing Maxi T cell phenotype from the lung tissue (> 60 dpi). (C) Percentage transgenic Maxi cells recovered from the lung are shown normalized to the total numbers recovered within the first week post transfer. Data are shown as mean + SEM of n = 13–17 mice pooled from five independent experiments. (D) Experimental setup: Naïve Maxi CD8 T cells were adoptively transferred into naïve C57BL/6 mice followed by i. v. MCMVΔm157 infection. Effector Maxi CD8 T cells were sorted from the lungs (7 dpi) and transferred into naïve recipients. (E) Representative contour plots showing Maxi T cell phenotype from the lung tissue (7dpi). (F) Percentage transgenic Maxi cells recovered from the lung is shown normalized to the total numbers recovered within the first week post transfer. Data are shown as mean + SEM of n = 10 mice pooled from two independent experiments. (G) Representative Bcl-2 histogram from effector and effector-memory Maxi CD8 T cells. Mean fluorescence intensities are shown + SEM of n = 6 mice pooled from two independent experiments. (C; E-F) ns, not significant; **p<0.01. Statistical analyses were performed using the non-parametric Mann-Whitney <i>U</i> test.</p>