Figure 4.

The armored B2ARM CAR maintains normal proliferative and degranulation capacity following long-term exposure to TGF-β, in contract to the non-armored CAR B2. Long-term co-cultures with target cells, MM.1S-GFP was achieved by repeatedly restimulating the co-cultured CAR T cells with target cells at ETT ratio of 0.1. Percentage expression of proliferation marker Ki67 (A), degranulation markers granzyme B and CD107a (B, C), respectively, as well as the apoptotic marker annexin V (D), by CAR T cells were evaluated by flow cytometry at the end of the long-term co-cultures (days 8-10). Total CD3+ cells were acquired by flow cytometry for analysis. Results represent mean ± SEM from 2 or 3 separate donors. Statistical significance was determined by one way ANOVA with Tukey’s post-hoc test.*p<0.05, **p<0.01, ns-non-specific.