IL-6 suppresses development of pre-cDC1. (A) pre-cDC1 (R1) in Zbtb46^egfp/+ mice defined by Grajales-Reyes et al. (2015). (B) Upper panel: Pre-cDC1 (R2) in Zbtb46^egfp/+ mice defined by Schlitzer et al. (2015). Lower panel: Cells in R2 were analyzed for cKit and Zbtb46-EGFP expression (R3 and R4). A bar-scatter graph shows the percentage (average % of R2 ± SD) of cKit^int R2 cells (R3) and cKit^lo R2 cells (R4). (C) Sort-purified cells from gate R1 in A and R3 and R4 in B were cultured in Flt3L for 3 d and analyzed by FACS. Arrows indicate the order of gating for successive histograms. Results are representative of three independent experiments. (D)Zbtb46^egfp/+ mice were inoculated i.p. with PBS, EL4-empty, or EL4-IL-6 tumor cells (10⁶ cells). BM cells were analyzed by FACS after 7, 10, 12, and 14 d as indicated. Numbers represent the percentage of Lin⁻ BM cells in the indicated gate (cKit^intZbtb46-EGFP⁺). (E) Shown are bar-scatter graphs for mice from D for the frequency of pre-cDC1 in Lin⁻ BM (average % ± SD). (F) Pre-cDC1 progenitor as defined in Grajales-Reyes et al. (2015) (R1 in A) from Zbtb46^egfp/+ mice at 14 d after inoculation. (G) Upper panel: Pre-cDC1 progenitor defined in Schlitzer et al. (2015) (R2 in B) from Zbtb46^egfp/+ mice at 14 d after inoculation. Lower panel: Analysis of R2 in upper panel for cKit and Zbtb46-EGFP⁺. (H) Bar-scatter graphs for frequency of pre-cDC1 as defined in F and G (average % of Lin⁻ BM ± SD). Individual mice are indicated as dots. *P < 0.05, **P < 0.01, ****P < 0.0001 (Student’s t test).