Page 121 - Haematologica Vol. 109 - July 2024

ARTICLE - Cytotoxic reprogramming for BiTE immunotherapy M. Casey et al. A
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Figure 2. Treatment with recombinant IL-21 augments cytotoxic granule release without affecting the production of pro-inflam- matory cytokines. (A) Peripheral blood mononuclear cells from healthy donors and JJN-3 myeloma were co-cultured for 3 days in the presence of T-cell-engaging bispecific antibody targeting B-cell maturation antigen (anti-BCMA T-BsAb) and indicated concentrations of recombinant interleukin-21 (rIL-21). Box-and-whisker plots showing levels of indicated effector proteins and cytokines in culture supernatants (N=8). (B) Representative histograms (left) and bar graphs (right), showing expression levels of CD69 in CD8 T cells 5 hours after stimulation with indicated concentrations of anti-BCMA T-BsAb and rIL-21. Data are shown as mean ± standard error of mean (N=5). (C) CTV-labeled peripheral blood mononuclear cells and JJN-3 myeloma cells were co-cul- tured for 3 days in the presence of indicated concentrations of anti-BCMA T-BsAb and rIL-21. Representative histograms (left) and bar graphs (right) showing CD8 T-cell proliferation (N=4). Data are shown as mean ± standard error of mean. (D) Represen- tative histograms (left) and box-and-whisker plots (right) showing expression levels of CD28 and CD226 in CD8 T cells after 3 days of co-culture in the presence of T-BsAb (0.1 μg/mL) and indicated concentrations of IL-21 (N=9). Data were pooled from 2 experiments, and differences were tested for statistical significance using a repeated measures ANOVA with a post hoc Dunnett’s multiple comparisons test. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001. CTV: CellTraceTM Violet; Gzm B: granzyme B; INF-γ: in- terferon-γ; TNF-α: tumor necrosis factor-α.
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