RT_Immunological Changes_interval

RT upregulated PD-L1 expression levels in tumor cells from the middle to late phase, which subsequently declined to a level comparable to baseline in the progression phase. When compared to 7.5 Gy, the frequency of PD-L1+ myeloid-derived suppressor cells with 2 Gy × 5 was maintained to be higher, showing tumor regression to a lesser extent. The proportion of PD-1+CD8+ and interferon-γ+CD8α T cells continued to increase until the end of the evaluation. The frequency of splenic PD-1+CD8+ T cells was significantly elevated following RT, and the effect was sustained longer with 2 Gy × 5. The transcriptomic data analysis revealed that RT stimulated the transcription of overall immunostimulatory and inhibitory genes, showing sequentially altered patterns. Each time point has 0Gy, 2Gyx5, and 7.5Gy samples. PreRT sample is a non-irradiated control group.