Fig. 4: CD229 CAR T cells target MM plasma cells and MM-propagating cells.
From: CD229 CAR T cells eliminate multiple myeloma and tumor propagating cells without fratricide
a Killing of MM cell lines by CD229 CAR T cells or ∆scFv CAR T cells as determined by luciferase-based cytotoxicity assay after 16 h co-culture. Data represent mean ± SD from three independent experiments. b Cytotoxic activity of CD229 CAR T cells or ∆scFv CAR T cells against malignant cells from three patients with plasma cell leukemia as determined by flow cytometry after 2–4 h co-culture. Data indicate mean ± SD from three patient samples. c Secretion of cytokines by CAR T cells during co-cultures with primary plasma cell leukemia cells as determined by cytometric bead assay. Data indicate mean ± SD from three co-cultures. Significance was calculated using two-sided Student’s t-test. NSG mice were injected with d 3 × 106 U-266 or e 1 × 106 RPMI-8226 cells expressing luciferase. After 1 week, mice were injected with 3 × 106 CAR T cells and bioluminescence was determined weekly. Differences in survival were determined by log-rank test. Data are representative of two independent experiments. f Killing of purified healthy B cells by CD229 CAR T cells or GFP T cells as determined by flow cytometry-based cytotoxicity assay. Data represent mean ± SD of three independent experiments. NSG mice were intravenously injected with 107 healthy PBMCs. After two days, mice were injected with 1 × 106 CD19 or CD229 CAR T cells or PBS and sacrificed after 4 days. B-cell numbers were determined in the animals’ g peripheral blood and h bone marrow. Data represent mean ± SD from three animals per group. Significance was determined by two-sided Student’s t-test. i In vitro cytotoxicity of CD229, ∆scFv, or BCMA CAR T cells against purified memory or naive B cells as determined by flow cytometry. Data represent mean ± SD from three independent experiments. j Bone marrow mononuclear cells from seven MM patients were co-cultured with CD229, ∆scFv, or BCMA CAR T cells for 4–6 h, depleted of CD3+ CAR T cells, and plated in methylcellulose. Colonies were counted after 14–21 days of culture. Data represent mean ± SD from seven patient samples. Statistical significance was determined by two-sided Student’s t-test. Source data are provided as a Source Data file.
