No. 88–7100-22; IL-12p70, Cat. No. 88–7121-22; TNF-α, Cat. No. 88–7324-22;

IL-6, Cat. No. 88–7064-22; IL-10, Cat. No. 88–7104-22) according to the manufacturer’s instruction. M-BMMs on day 5 from WT and Klf10-deficient mouse were stimulated with 1 μg/mL LPS for 12 and 24 h. Culture supernatants were analyzed for NO by the Griess reaction. Briefly, 50 μL supernatant was incubated with 50 μL Griess reagent for 5 min at room temperature, and NO2 level was determined by measuring the absorbance at 540 nm relative to the reference sample. Whole cell lysates were prepared by complete Lysis-M Bcl-2 inhibitor kit (Roche; Cat. No. 04719956001) and the concentration was determined PD-1/PD-L1 activation by the bicinchoninic acid protein assay (Thermo Scientific; Lot # MC 155209). The same amounts of protein were resolved on SDS-PAGE gels, transferred to polyvinylidene fluoride membrane. After blocking with 5% nonfat dry milk/PBS, the membranes were further incubated with the indicated primary antibodies overnight, reacted with a secondary antibody, and then protein bands were visualized by ECL. Cells were harvested and incubated with relative antibodies for 30 min on ice, washed, and analyzed in a FACS calibur flow cytometer (Becton Dickinson).

The promoter of IL-12p40 and its mutants were produced by PCR-based Unoprostone amplification and subcloned into the pGL3-Enhancer Vector to forming luciferase report plasmid. Human embryonic kidney (HEK293) cells were cotransfected with 100 ng luciferase reporter plasmid, 10 ng thymidine kinase promoter-Renilla luciferase reporter plasmid, plus the pCDNA3-Klf10, or control vector. After 48 h, luciferase activities were determined by the Dual-Luciferase Reporter Assay System (Promega, Cat. No. E10910) according to the manufacturer’s instructions. The primers were as followed: P40-promoter-WT: CTCGAGTAGGCATGATGTAAACAGAAAT,   AAGCTTCTAGATGCAGGGAGTTAGC P40-promoter-Δ: CTCGAGTCATTTCCTCTTAACCTGGG,   AAGCTTCTAGATGCAGGGAGTTAGC P40-promoter-mut:

CTCGAGTAGGCATGATGTAAACAGAAATTA   GTATCTCTGCCTCCTTCCTTTTTCCAATCCCCGA,   AAGCTTCTAGATGCAGGGAGTTAGC Chromatin-immunoprecipitation assays were done essentially as the manufacturer’s protocol (Active motif, CHIP-ITTM Express). The immunoprecipitated DNA fragments were then analyzed by semi-qPCR and qPCR. The primers used were as followed: GAPDH: TTACTTTCGCGCCCTGAG, GCGGTTCATTCATTTCCTTC IL-12p40: TGCCGCCTCTATTCACCTTA, CTGACTAGTCTCAATTGCAACA Data are presented as the mean ± SD. Statistical significance was determined by Student’s t-test. A value of p < 0.05 was considered to be statistically significant. We thank L. Lu for discussions; F. Xing for assistance with manuscript editing.