Fig 4. Persistent infection promotes Tem survival.

A) Schematic representation of the experimental design. Memory T cell subsets were sorted from infected B5 TCR Tg mice (d60 p.i.) and the same number of each subset (2.5 x 10⁵) were transferred into either infection-matched (d60 p.i., top) or uninfected (bottom) Thy1.1 hosts for 60 days after transfer. B) Graph shows numbers of recovered B5 T cells (CD4⁺ Thy1.2⁺) in recipients of Tem^Early. C) Concatenated contour plots show division (CFSE-), and levels of CD127, and phenotypes (CD62L, CD27) of cells recovered from Tem^Early recipients. Summary bar graphs show average of divided cells or fraction in each Tmem subset gate on recovery. D) Graph shows numbers of recovered B5 T cells in recipients of Tem^Late. E) Concatenated contour plots show levels of CFSE, and CD127, and phenotypes (CD62L, CD27) of cells recovered from Tem^Late recipients. Summary bar graphs show average of divided cells or fraction in each Tmem subset gate on recovery. Data are representative of 2–4 mice per group from 2 similar experiments. Data was analyzed by Student’s t test, and error bar represents SEM, *p<0.05, n.s.–not significant. On summary bar graphs symbols refer to differences between fractions of recovered cells in each Tmem subset in a given stacked bar, one symbol = p<0.05; two symbols, **p<0.01 comparing Tcm to TemL; three symbols, ***p<0.001 comparing Tem^Early to Tem^Late, ^# comparing Tcm (very few) to Tem^Early, ⁺ comparing Tem^Early to Tem^Late.