Enhanced abscopal antitumor effects in A20 lymphoma model with fractionated RT. (A) Working model: time line and schematic representation of in vivo A20 tumor–bearing mice treated with 2 × 4-Gy or 1 × 8-Gy RT in 1 of the 2 tumors. (B-C) A20 tumor growth from irradiated and nonirradiated abscopal tumor as followed by caliper measurements (n = 5-6 mice). (D) Gene ontology terms that are significantly enriched with an adjusted P value <.05 in the differentially expressed gene sets. Data represent irradiated tumors from the fractionated- or single-dose–treated groups. (E-F) Gene expression of granzyme B (gzmb) and perforin 1 (prf1) in irradiated and nonirradiated tumor 5 days after RT. (G-H) CD45⁺/CD3⁺ and CD45⁺/CD3⁺/CD8⁺ T-cell infiltration in irradiated and abscopal tumors 34 days after tumor implantation. Graphs show the mean ± standard error of the mean (SEM). ∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001. Data are representative of 3 independent experiments. CTR, control; ns, not significant; SARRP, Small Animal Radiation Research Platform.