Fig. 1: BNCT induces robust and long-term systemic immune responses.

a Principle of the ¹⁰B(n,α)⁷Li reaction. b Principle of boron neutron capture therapy compared with X-ray radiotherapy. X-ray radiation non-selectively kills cells, causing immune cell dysfunction and increasing the potential risk of cancer recurrence. BNCT selectively kills boron-containing cancer cells while sparing the surrounding healthy tissue, especially immune cells. DAMPs, damage-associated molecular patterns. c–h Abscopal effect assay. c, f Treatment schemes for the B16F10 (c) and MC38 tumour models (f). C57BL/6J mice, 6–8-week-old, female, n = 6 mice for each group tested. d, e Average tumour volume of irradiated (d) and non-irradiated B16F10 tumours (e). NC, negative control. g, h Average tumour volumes of irradiated (g) and non-irradiated MC38 tumours (h). The green line showed the tumour growth curve in the non-irradiated regions of mice without right-side tumour implantation but with identical boron injection and neutron irradiation. i–m Tumour vaccination assay. i Treatment scheme. Average tumour volume (j) and survival fraction (k) of each group of B16F10-bearing mice (n = 5 mice for each group tested), two-tailed unpaired Student’s t-test, NC vs BNCT, **p = 0.0060, X-ray (4 Gy) vs BNCT, **p = 0.0020. Average tumour volume (l) and survival fraction (m) of each group of MC38-bearing mice (n = 5 mice for each group tested), two-tailed unpaired Student’s t-test, *p = 0.0274, ****p < 0.0001. n–q Tumour rechallenge assay. n Treatment scheme. Average tumour volume (o) and survival fraction (p) of each group of MC38-bearing mice (n = 5 mice for each group tested). NC-R, right tumour of the negative control group; BNCT-R, right tumour of the BNCT group; NC-L, rechallenged left tumour of the negative control group; BNCT-L, rechallenged left tumour of the BNCT group. q Quantification of naïve (CD44^lowCD62L^high), central memory (CD44^highCD62L^high, Tcms), and effector memory (CD44^highCD62L^low, Tems) CD8+ T cells in the blood. n = 5 mice for each group tested, two-tailed unpaired Student’s t-test, *p = 0.0250, *p = 0.0380, and *p = 0.0476, respectively. The data are the means ± SEM. Source data are provided as a Source Data file.