Skip to main content
Fig. 2 | Journal of Hematology & Oncology

Fig. 2

From: Homogeneously high expression of CD32b makes it a potential target for CAR-T therapy for chronic lymphocytic leukemia

Fig. 2

CD32b CAR-T efficacy against Raji cells and primary CLL cells. a Diagram indicating constructions of two CD32b CAR sequences (scFvs from clone 2B6 or NOV2108). b NOV2018 scFv binds Ig-like C2-type 1 domain of CD32b, whereas 2B6 binds binding domain of CD32b. c Cytotoxicity of CD32b CAR-T targeting Raji cells after incubation for 36 h at the indicated effector-to-target (E: T) ratios; control T cells were used as negative controls. d Schematic of the Raji xenograft model. NSG mice were injected via tail vein with 3 × 105 luciferase+ Raji cells on day-5. Bioluminescent imaging was performed on day 0 to quantify engraftment and then weekly measured. Control T cells or 2B6bbz T cells (1 × 106) were injected IV on day 0. e Representative bioluminescent imaging at day 0, 7, 14 and 42 after injection of Raji cells. f Flow cytometric analysis of Raji cells in peripheral blood from Raji-NSG mice (from e). g Bioluminescent signal for each treatment group over time. Data represent mean values of each group ± SD. h Log-rank survival curve was used for survival analysis of Raji xenograft mice treated by 2B6bbz or control T cells. Data of g and h were summarized from 4 independent experiments. (Control, n = 12; 2B6bbz, n = 14). i Flow cytometric analysis of CAR-T cells in peripheral blood from Raji-NSG mice (from e). j Specific cytotoxicity targeting of CLL by 2B6bbz and CD19 CAR-T cells after incubation with primary CLL cells for 36 h at the indicated E:T ratios; Three representative CLL patient examples are shown. k Correlation between 2B6bbz T cytotoxicity and CD32 density across different patient CLL samples. l Schematic of the primary CLL xenograft model. NSG mice were sublethally irradiated (150 cGy) on day -3 and injected with 2–4 × 107 CLL PBMCs via the tail vein on day -3. Engraftment was confirmed by flow cytometry in PB around day 0. Mice were then injected with 5 × 105 2B6bbz T, CD19 CAR-T cells or control T cells via the tail vein and bled weekly to quantify CLL burden. m Response of primary CLL-NSG mice treated with 2B6bbz T (CC, n = 8; NC, n = 2), CD19 CAR-T (CC, n = 4; NC, n = 6) or control T cells (NC, n = 10). n Number of CAR-T and tumor residue in PB, BM, liver and spleen from CLL-NSG mice after receiving CAR-T cells for 18 days. Data of m and n were summarized from four independent experiments. M indicates mouse. CC, complete clearance (defined as tumor residual less than 0.001% in all the tissues detected); NC, not clearance (mouse couldn’t be defined as CC); BM, bone marrow; PB, peripheral blood. Chi-square test was used for statistical analysis in m. Log-rank (Mantel–Cox) test was used for statistical analysis in h. Unpaired two-tailed Student's t test was used for statistical analyses in g and j. Pearson correlation analysis was used in k. (*P < 0.05, **P < 0.01, ***P < 0.001)

Back to article page