Antimyeloma effects of mAb/B-BiTE-redirected human T cells and NK cells. (A) Expression patterns of CD38 and SLAMF7 on myeloma cell lines. (B-C) CD19– human PBMCs derived from 5 different donors were incubated with target myeloma cell lines in the presence of the indicated antibodies including daratumumab/B-BiTE (B) or elotuzumab/B-BiTE (C) (mAb, 7.5 μg/mL; B-BiTE, 2.5 μg/mL), and assessed for their multiple cytokine production and CD107a upregulation. CD8+ T cells triple-positive for IFN-γ/TNF-α/CD107a, CD4+ T cells triple-positive for IFN-γ/TNF-α/IL-2, and NK cells double-positive for IFN-γ/CD107a were measured by flow cytometry. Each dot represents each donor. Expression level of CD38 (B) or SLAMF7 (C) in each cell line is labeled according to the result in panel A. The paired t test (2-sided) was performed for comparison, and error bars show the SD. (D) CD19– PBMCs were incubated with target cells in the presence of the indicated antibodies (mAb, 7.5 μg/mL; B-BiTE, 2.5 μg/mL) at different E:T ratios, and their cytotoxicity was examined using chromium-51 (51Cr)–release assays. All the experiments were performed in triplicate, and error bars show the SD. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001; E:T, effector to target; n.s., not significant; SD, standard deviation.
