Figure 2. Macrophages devoid of STAT3 cross-present antigen acquired from a tumor cell more efficiently than WT macrophages.
(A) STAT3-deficient but not WT macrophages can capture and cross-present antigen from irradiated A20HA tumor cells and stimulate proliferation in CLN4 CD8 T cells responding specifically to HA antigen. (B) In the context of HA antigen presented by STAT3-deficient macrophages, intracellular cytokine staining shows that proliferating CLN4 T cells produce measurably more IFN-γ. (C) Similar results are seen when EL4mOVA tumor cells are used as an antigen source for B6.Stat3KO macrophages, with OVA-specific OT-I CD8 T cells used a measure of cognate stimulation.