Poly(A:U)-induced LIC expansion in vivo is an age-dependent outcome. (A) 6-day-old Eμ-Ret pups were injected with indicated PRR ligands, and LIC burden was evaluated 7 days later and analyzed using Dunnett multiple comparison test. (B) 4- to 6-week-old Eμ-Ret mice were treated with either phosphate-buffered saline (PBS) or Poly(A:U), and LIC burden after 7 days was evaluated. (n = 5 for PBS and n = 5 for Poly(A:U)). In all experiments, cell counts were quantified using CountBright beads. Unpaired t test; bars represent mean ± SD; ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001; ns.