Fig. 5: rhIL-7-hyFc improves the anti-tumor efficacy of mCART19 in immunocompetent mice.
a Balb/c mice were given sublethal irradiation (600 cGy), followed by injection with a syngeneic B cell lymphoma cell line, A20CBR-GFP, either 5 × 105 cells intravenously (IV) or 1 × 106 cells subcutaneously (SC), then given 5 × 105 mCART19 cells and serial injections of rhIL-7-hyFc on days +1 and +15 (n = 4–5/group). b Absolute numbers of peripheral blood CAR T cells in each group measured at day +57. Lines represent median values, with each data point representing one mouse (IV A20 + CART + rhIL-7-hyFc vs. CART only, p = 0.017, SC A20 + CART + rhIL-7-hyFc vs. CART only, p = 0.002). c For mice given A20 IV, BLI measurements of tumor burden (left, each line represents one mouse), and overall survival (mCART19 vs. mCART19+rhIL-7-hyFc, p = 0.13, mCART19 vs. rhIL-7-hyFc only, p = 0.04). d For mice given A20 SC, BLI measurements of tumor burden (left, each line represents one mouse), and overall survival (mCART19 vs. mCART19+rhIL-7-hyFc, p = 0.016, mCART19 vs. no treatment, p = 0.018). e, f Day +57 peripheral blood flow cytometry evaluation of naive (T-N), central memory (T-CM), effector memory (T-EM), and effector (T-EFF) T cell populations within endogenous and CAR T cells with and without rhIL-7-hyFc, subdivided by CD4+ and CD8+ T cells. For this analysis, values from mice that received IV and SC tumor were pooled for each group (no rhIL-7-hyFc: n = 6, +rhIL-7-hyFc: n = 10). T cell memory subsets were defined using expression of CD62L and CD44 as indicated in f. e Proportions of T-N, T-CM, T-EM, and T-EFF within the CD4+ and CD8+ T cells in endogenous T cells and mCART19. Bar graphs represent median values, with each data point representing one mouse. p Values are provided in the Source data file. f Fold-change of T cell subsets were calculated by averaging the absolute numbers of each cell subset, and dividing the numbers for mCART19+rhIL-7-hyFc treated mice over mCART19 only controls. CART4 = CD4+ CAR T cells, CART8 = CD8+ CAR T cells, 4 = endogenous CD4+ T cells, 8 = endogenous CD8+ T cells. g Long-term surviving mice were rechallenged with 1 × 106 A20 cells (without CBR-GFP) IV on day +100. A separate cohort of mice with no prior treatment was also injected with A20 tumor cells on the same day as controls (n = 4). h Peripheral blood CAR T cell numbers at day +28 post-rechallenge. mCART19+rhIL-7-hyFc (n = 9) vs. mCART19 (n = 3), p = 0.014. p values for survival curves were calculated using two-sided log-rank test, and for b, e, h by two-sided unpaired Student’s t test. Source data are provided as a Source data file. No tx: no treatment, ns: not significant, *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001.
