LAPCs control viral replication in the lung via modulating humoral responses in IAV infection. (a) Both WT (n = 9) and Cxcr3^−/− mice (n = 18) were infected with A/PR/8 virus (0.05 LD50). At 2 dpi, groups of IAV-infected Cxcr3^−/− mice (n = 12) received different inocula of 8 dpi LAPCs (mPDCA1⁺CD11c⁻B220⁻TcRβ⁻), (2.5 × 10⁵ [LI] or 5 × 10⁵ [HI] cells/mouse), i.v., isolated from the dLNs of different A/PR/8 virus-infected B6 mice. (b) Antiinfluenza Ab responses (IgM and total IgG) and (c) infectious viral titers were determined in the BAL fluid (BALF) by Ab-ELISA and TCID₅₀ assays, respectively, as described in Materials and methods. Combined data of two independent experiments are shown as means ± SEM. Considered a significant difference at * (KO vs. WT), ** (KO vs. KO+ LI LAPC) and *** (KO vs. KO + HI LAPC), P < 0.05.