Impaired cross-priming in Nfil3^−/− mice. Nfil3^−/− and Nfil3^+/+ mice were immunized with irradiated K^b−/−/mOva splenocytes intravenously. Detection of OVA₂₅₇-specific CD8⁺ T cells in PBLs and spleen by tetramer (K^b/OVA₂₅₇) staining was performed at day 5 after immunization. (A) Representative FACS profiles for OVA₂₅₇-specific CD8⁺ T cells in PBLs. Similar results were obtained from 3 independent mice in each group. (B) Reduced frequency of OVA₂₅₇-specific CD8⁺ T cells among total circulating CD8⁺ T cells in Nfil3^−/− PBLs at day 5 after immunization. Each dot represents an individual Nfil3^+/+ mouse (○) or Nfil3^−/− (●) mouse, and gray lines indicate mean frequency (*P = .0016). (C) Representative FACS profiles for OVA₂₅₇-specific CD8⁺ T cells in spleen. Similar results were obtained from 3 independent mice in each group. (D) Reduced frequency of OVA₂₅₇-specific CD8⁺ T cells of Nfil3^−/− spleen CD8⁺ T cells at day 5 after immunization. Each dot represents an individual Nfil3^+/+ mouse (○) or Nfil3^−/− mouse (●), and gray lines indicate mean frequency (**P = .0067). (E) Reduced numbers of OVA₂₅₇-specific CD8⁺ T cells in Nfil3^−/− spleen at day 5 after immunization. Data represent 1 of 2 independent experiments with similar results (***P = .035). (F) Detection of CD8α⁺ cDCs (CD11c^hiCD8α⁺DEC-205⁺SIRP-a^lo) in Nfil3^−/− and Nfil3^+/+ mice immunized with irradiated K^b−/−/mOva splenocytes by flow cytometry. Data are representative of 3 independent mice from each group.