Figure 2.

IL-15-grown ARI2h BCMA-CARs are highly functional. UT and ARI2h-transduced (ARI2h^IL-2, ARI2h^IL-15, ARI2h^IL-15/IL-7, ARI2h^None) T cells were co-cultured with ARP-1 cells for 24 h (A), 96 h (B) or 6 h (C–F) or U266 cells for 24 h (A). (A) Survival of GFP-ffLuc-expressing ARP-1 (left) or U266 (right) multiple myeloma (MM) cell lines, following a 24-hour co-culture with UT or ARI2h cells at the indicated T cell:tumor cell line (effector:target) ratios (n = 5). (B) Survival of GFP-ffLuc-expressing ARP-1 cells following a 96-hour co-culture with UT or ARI2h cells, measured every 24 h. Graphs show the results of a first co-culture (left) and a second challenge (right) of ARI2h^IL-2, ARI2h^IL-15 and ARI2h^IL-15/IL-7 cells with fresh ARP-1 cells. All challenges were performed at a 0.125:1 effector:target ratio (n = 3). (C,D) Levels of released IFNγ (C) and IL-2 (D), as measured by ELISA. (E) Summary of the surface expression of CD107a on CD8⁺ (UT) or CD8⁺ CAR⁺ T cells, based on the MFI and normalized to UT. (F) Left—representative histograms showing granzyme B staining in UT or CAR⁺ CD4⁺ and CD8⁺ T cells. Right—summary of the granzyme B expression in CD8⁺ (UT) or CD8⁺ CAR⁺ T cells, based on the MFI and normalized to UT. * p < 0.05.