Defects in DC uptake of Lm, in reduced MHC and costimulatory molecule expression, and in accumulation of the critical CD8α+ DC subset at discrete times post-infection, provide another piece of the puzzle explaining why aged mammals fail to mount robust CD8 T-cell responses to Listeria. We conclude that both CD8 T-cell-intrinsic and environmental/antigen presentation issues contribute to impaired adaptive immune responses against intracellular bacterial pathogens in aged mice and suggest targeted manipulations to correct this defect. The gene discussed is CD8A; the disease is infection.