Mature NK cells fail to accumulate in the D-LN of aged mice. (A) Young and aged mice were infected with 3,000 PFU WT ECTV and euthanized 2 dpi. D-LN and ND-LN were made into single cell suspension and surface stained for CD3, NK1.1, CD11b, and CD27. Column graphs show the means ± SD for the proportion of cells within the NK1.1⁺CD3⁻ population (NK cells) that were CD11b⁺ and CD27⁻ (mature R3 cells). Gray columns, young mice; white columns, aged mice. Representative flow cytometry plots are shown with those from uninfected control mice for comparison. (B) As in A, but the mice were infected with ECTV Δ166. Data correspond to three experiments with three mice/group.