Figure 4.

Delta-24-GREAT induced antitumor memory effect and generation of central immune memory. (A) Schema of the preclinical rechallenge study. (B and C) C57BL/6 mice treated with Delta-24-GREAT that survived after GL261-5 intracranial implantation (n = 6) were re-challenged with intracranial injection of GL261-5 (B) (5 × 10⁴ cells; n = 3) or B16/F10 melanoma cells (C) (1 × 10³ cells; n = 3) in their contralateral, left hemisphere. Naïve mice with similar age were used as control (n = 3). Data are represented as Kaplan–Meier curves. P values are shown (log-rank test). (D) Surviving mice from experiment depicted in (B) were intracranially implanted again with GL261-5, and 21 days later cervical and axillary lymph nodes were collected and analyzed by flow cytometry (n = 3). (F and E) Central memory T cells (CD44⁺CD62L⁺) in CD45+CD3+CD4+ and CD45+CD3+CD8+ cells were quantified in lymph nodes from mice treated with Delta-24-GREAT. Naïve mice with similar age (bearing tumor, no treatment) were used (n = 3). Data are represented as mean ± SD. ns = not significant; *P < .05, Student’s t-test, double sided. (E) Representative flow cytometry dot plot of CD44⁺CD62L⁺ central T memory analysis.