CD20-BsAbs increase killing by expansion of CD19-CAR T cells in vitro. (A) The percentage of viable lymphoma cells and x-fold expansion of T cells in cocultures of B-cell lymphoma cell lines and CD19-CAR or NT T cells in the presence or absence of 100 ng/mL CD20-BsAb are shown for 46 different cell lines. (B) The cellular composition is shown for primary B-cell malignancy samples from patients as determined by flow cytometry. Samples are ordered by decreasing T-cell content (n = 24 samples). The percentage of viable lymphoma cells (C), x-fold expansion of endogenous T cells (D), and x-fold expansion of added CD19-CAR or NT T cells (E) in cocultures with primary B-cell malignancy samples in the presence or absence of 100 ng/mL (low concentration) or 1000 ng/mL (high concentration) CD20-BsAb are shown for n = 24 samples. Cocultures were performed using an effector (E) to target (T) cell ratio of 0.2:1. The percentage CD25⁺, GrB⁺, and Ki67⁺ T cells among CD4⁺ or CD8⁺ endogenous (F) or CD19-CAR or NT (G) T cells in the presence or absence of 1000 ng/mL CD20-BsAb in n = 24 samples. P values were calculated using the 2-sided, paired Wilcoxon test (A,C-G). ∗∗∗P ≤ .001, ∗∗P ≤ .01, ∗P ≤ .05. ns, not significant.