Fig. 3.

CD8⁺NKT-like cells kill the tumor antigen-bearing MDSCs. a Mice were subcutaneously inoculated with EL4 cells or EL4-OVA8 cells. When the tumor size reached 1 cm³, tumors were resected and digested with 1 mg/mL collagenase IV. Intratumoral MDSCs were identified as CD11b⁺Gr-1⁺ cells and stained with antibodies against H₂K^b-bound OVA_257–264 peptides. b MDSCs and OVA-specific CD8⁺NKT-like cells were co-cultured at an E:T ratio of 10:1 with or without OVA peptide. After 24 h, 7-AAD-negative live MDSCs were collected and counted by flow cytometry. Relative number of live MDSCs is shown as histograms. c CD8⁺NKT-like cells or NK1.1⁻CTLs from OT-I mice were co-cultured with MDSCs at an E:T ratio of 10:1 with OVA peptides. After 24 h, 7-AAD-negative live MDSCs were collected and counted by flow cytometry. Relative number of live MDSCs is shown as a histogram. d Dynamics of the killing process of OVA_257–264 antigen-loaded MDSCs by CD8⁺NKT-like cells or NK1.1⁻CTLs are shown. Flow cytometry analysis of OVA peptide-loaded MDSCs was performed in three independent experiments where n = 3 in each experiment. In vitro experiments were performed in triplicate and repeated three times with similar results