Fig. 4

MDSC of treated mice do not acquire professional antigen presenting cell function. a-b Schematic representation of differential gene expression upon poly(I:C)_c treatment annotated in the KEGG pathway antigen processing and presentation of PMN- and M-MDSC. c-g Mice with orthotopic ovalbumin expressing PDAC (T112099-OVA) were treated with poly(I:C)_c twice prior to sacrifice at day 21 after tumor implantation. c-d Surface expression of MHC-I and CD86⁺ of MDSC populations at baseline and upon poly(I:C)_c treatment. e-g MDSC from (e) tumor and (f-g) spleen of untreated or poly(I:C)_c-treated tumor-bearing mice were isolated. Splenic MDSC were either treated with OVA protein (f) or SIINFEKL peptide (g). Subsequently MDSC were co-cultured with CFSE-labelled OT-I T cells with an increasing effector (E; MDSC) to target (T; T cell) ratio (E:T) of 0.25:1, 0.5:1 and 1:1 and CFSE dilution of CD8⁺ T cells was assessed following 72 h of co-culture. c-d Data are shown for n = 5 to 6 mice per group. e-g Representative graph of two independent experiments, Data± SEM for n = 2 mice per group (n.d. = not determined; *p < 0.05; **p < 0.01)