MPPE1 and melanoma: We used the poorly immunogenic B16-F10 melanoma cell line engineered to express the model antigen OVA fused to mCherry and a 17-amino acid LA F-actin binding peptide (B16-F10 LA-OVA-mCherry).9 We found that effective and sustained control of B16-F10 LA-OVA-mCherry tumors following a single fraction of X-ray irradiation was lost in Batf3–/– mice lacking cDC1 or Rag1–/– mice lacking T and B cells (figure 1E).