Adoptive transfers and infections were performed as described (Smith et al. 2014 (link)). Briefly, CD8+ T cells were isolated from congenically marked adult and neonatal mice, mixed at a 1:1 ratio, and 2 × 104 cells were transferred intravenously into Ly5.2 recipients. The next day, recipients were intravenously infected with Lm-gB (5 × 103 CFU). Effector CD8+ T cells from recipient spleens were isolated with anti-CD8 beads (Miltenyi Biotec) and then sorted via congenic marker expression on a FACS Aria (BD Biosciences).