2.7. Xenograft tumor model

Here, 6‐wk‐old female CAnN.Cg‐Foxn1nu/CrlVR (BALB/c) mice weighing 20.12 ± 1.45 g (n = 50; Beijing Vitonlihua Experimental Animal Technology Co., Ltd) received 1 × 10⁷ Raji cells transduced with luciferase (purchased from Shanghai Super Biotechnology Co.) by subcutaneous injection, followed by bioluminescence imaging (BLI) monitoring twice a week. Upon confirmation of engraftment after 25 d, the mice were randomized into an ibrutinib (8 mg/kg/d) monotherapy group, a CD19 CAR‐T‐cell (2 × 10⁷/kg) monotherapy group, an ibrutinib combined with CD19 CAR‐T cells group, and an ibrutinib combined with T cells (2 × 10⁷/kg) group. The CD19 CAR‐T cells and T cells generated from the same donor (patient no. 7 who did not respond to CAR‐T‐cell therapy) were administered to the tail vein on day 0. Ibrutinib was administered daily to the mice by oral gavage. There were 5 mice in each group. On day 0, day 14, and day 28, mice were monitored using BLI for disease progression following intraperitoneal injection with d‐luciferin (Goldbio, 150 mg/kg) 10 min before scanning. Before imaging, mice were anesthetized via a nose cone with 2% isoflurane (Zoetis) medical oxygen and maintained under inhalational anesthesia. All mice were sacrificed when either experimental or human endpoints were reached.

Another group of the same mice was injected with 1 × 10⁷ Raji lymphoma cells by tail vein injection to establish an animal model. Upon confirmation of engraftment after 10 d, these mice were separated randomly into various groups as in the subcutaneous tumorigenic mouse models. The CD19 CAR‐T cells, T cells, and ibrutinib were utilized in the same way as in the subcutaneous tumorigenic mouse models. There were 5 mice in each group. The proportions of lymphoma cells in the epicanthus vein on days 0, 7, 14, 21, and 28 were analyzed by FCM. The proportions of lymphoma cells in the bone marrow on day 21 were also analyzed by FCM.