Spatial Zonation of Pro- and Anti-inflammatory Tumor Macrophages After Anti-CD40 II

Because necrosis can be induced by multiple therapeutic modalities, we next analyzed irradiated MC38 tumors to see if they similarly exhibit Spp1+–Cxcl9+ polarization. Therefore, we conducted a spatial RNA-seq analysis on MC38 tumors at 24 hours and 7 days post–irradiation with 12 Gy. As observed under anti–CD40–mediated immunotherapy, we discovered that phenotype heterogeneity among Lyz2+ features increased over time, reproducing the bifurcated polarization trajectory along the Spp1–Cxcl9/Cxcl10 axis. High-resolution macrophage profiling similarly confirmed the regional segregation of Cxcl10+ (better detected in these samples than Cxcl9) and Spp1+ cells. Overall design: spatial RNA-seq analysis on MC38 tumors at 24 hours and 7 days post–irradiation with 12 Gy