Figure 7.

Tumor lysates generated by histotripsy confer partial protection when administered as vaccines. Mice bearing B16F10 tumors were treated with no therapy, 15 Gy radiation therapy (XRT), or histotripsy (“HT”) ablation on day 9. Tumors were explanted on day 10 and untreated tumors were dissociated by 3 cycles of alternative freezing and thawing. The resulting lysates were centrifuged to generate cell-free fractions, and fractions were delivered via intraperitoneal injection into naïve mice one day prior to B16F10 flank injection. (A, B) Whereas vaccination with tumor lysates generated by XRT or freeze-thaw conferred no protection against B16F10 challenge tumor growth as compared with unvaccinated controls, mice receiving tumor lysates generated by histotripsy exhibited slower challenge tumor growth kinetics. (C) Multicolor immunohistochemistry of challenge tumors growing in unvaccinated control and HT lysate-vaccinated mice showed marked increases in both CD8+ cell infiltration and 4-HNE accumulation. (n=3-6 mice per group; *=p<0.05 compared with controls).