Fig. 8: IL-9 induces IL-6 expression in Arg1 expressing IMs.

a Dot plot showing IL6 expression in different clusters from human lung cancer patients scRNA-Seq. b Naive mice were i.v injected with IL-9 for 4 days, IL-6 expression in IMs was analyzed (n = 4 mice). c IL6 expression in human PBMC monocyte derived M2 macrophage (n = 3 donors). d Serum IL-6 level in B16 tumor bearing mice (n = 9 mice for WT group, n = 8 mice for Il9r^−/− mice). e IL-6 expression was analyzed by gating on Arg1⁺ or Arg1⁻ macrophages from WT B16 tumor bearing mice (n = 9 mice). f Serum IL-6 level from mice described in Fig. 6f were analyzed by ELISA (n = 10 mice for Arg1⁺ Mac group, n = 12 mice for Arg1⁻ Mac group, n = 5 mice for PBS group). g Arg1⁺ or Arg1^- macrophages were sorted from entire lung of tumor bearing mice and plated in the lower chamber of the transwell; B16 tumor cells were placed in the upper chamber. Cells were allowed to migrate for 12 h (n = 4 mice). h Arg1⁺ or Arg1⁻ macrophages were sorted from entire lung of tumor bearing mice and cultured for 24 h, IL-6 concentration was analyzed (n = 3 mice). i, j Mixed bone marrow chimeric mice were generated and injected with B16 tumor as described. Donor derived IL-6⁺ Arg1⁺ IMs were analyzed by flow cytometry, dot plots were gated on live IMs (n = 9 mice). k–m WT tumor-bearing mice were treated with isotype antibody or anti-IL-6 antibody as shown in k, tumor growth (l) (n = 3 mice for isotype group, n = 5 mice for anti-IL-6 group) and survival (m) (n = 12 mice) were analyzed. Unpaired two-tailed Student t-test was used for comparison in b, c, d, e, h and l. Data are the mean ± SEM. One-way ANOVA with a Dunnett’s multiple comparison test was used for multiple comparisons in f. Paired two-tailed Student t-test was used for comparison in j. Two-way ANOVA with Sidak’s multiple comparisons was used for comparisons in g.