Fig. 5

Bidirectional control of MDSC suppressive function by type I interferon signaling in PDAC. Wild type and IFNAR1-deficient mice were transplanted with T110299 orthotopic tumors and treated with poly(I:C)_c twice prior to sacrifice at day 21 after tumor induction. a Tumor weights, CXCL10 and IL-6 serum levels in untreated and treated mice. b Splenic MDSC frequency. c-d MHC-I and PD-L1 surface expression on splenic MDSC. e-f T cell frequency and CD69 expression on splenic T cells. g Splenic T cells from untreated C57BL/6 mice and MDSC from spleens of T110299 tumor-bearing wild type or IFNAR1-deficient mice were isolated and T cell suppression was analyzed ex vivo. T cells were co-cultured with an increasing effector (E; MDSC) to target (T; T cell) ratio (E:T) of 0.25:1, 0.5:1 and 1:1 for 72 h in the presence of anti-CD3/anti-CD28 mAb-coated beads. CFSE dilution of CD4⁺ and CD8⁺ T cell populations was assessed. a-f Data ± SEM is shown for n = 4 to 7 mice per group. g Data± SEM for n = 3–5 mice per group, unpaired two-sided students t test(*p < 0.05; **p < 0.01, (g) comparison of untreated wild type and untreated IFNAR1-deficient are depicted with *; #p < 0.05, ##p < 0.01, comparison of untreated wild type and treated wild type are depicted with #)