Figure 3.
AG2G-expressing T cells differentiate between cells expressing high and low antigen levels, are more specific, and less exhausted, compared with classic CAR T cells. A, Mean numbers of HT29 cells expressing HER2, calculated by incuCyte software, following incubation with transduced T cells in combination with antibodies (60 μg/mL each, n = 4). B, ELISA measurement of IFNγ levels in 48-hour supernatants of AG2G-transduced T cells incubated with HER2-expressing HT29 target cells, and with tumor-binding trastuzumab, or irrelevant antibodies cetuximab and rituximab (60 μg/mL). C, Mean counts of HT29 cells expressing HER2, calculated by incuCyte software, following incubation with AG2G-transduced T cells and 30 μg/mL trastuzumab, compared with trastuzumab-derived CAR (4:1 E:T ratio, n = 4). Each sample is normalized to its cell number at time zero. D, Normalized confluence of kidney epithelial cells, calculated by incuCyte software, following incubation with AG2G-transduced T cells and 30 μg/mL trastuzumab, compared with trastuzumab-derived CAR (4:1 E:T ratio, n = 4). Each sample is normalized to its cell confluence at time zero. E, ELISA measurement of IFNγ levels in 48-hour supernatant obtained from transduced T cells and kidney epithel described in D (n = 4). F, ELISA measurement of IFNγ, granzyme B and TNFα levels in 24-hour supernatants of 105 AG2G-expressing T cells or CAR T cells incubated on immobilized trastuzumab or rHER2, in rising concentrations (mmol/mL) respectively. G, Confocal microscope imaging of internalization kinetics of PE-labeled IgG by AG2G-expressing cells (top), or PE-labeled HER2 by CAR T cells (bottom). H, PD-1, LAG-3, and TIM3 flow cytometry analysis of AG2G-expressing cells or CAR T cells after 48-hour incubation with or without 12 mmol/mL immobilized trastuzumab or HER2, respectively. Graphs show mean ± SD. Statistical significance was calculated using two-way ANOVA with Tukey's correction for multiple comparisons for A, C, D, and H. Two-way ANOVA with Sidak correction for multiple comparisons for E and F. One-way ANOVA with Dunnett correction for multiple comparisons for B. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001. Error bars represent standard error.