Figure 4. Primary human T cells transduced to express huEGFRt/DHFR^FS/IMPDH2^IY can be selected in vitro with MTX and MPA.

(a), Representative flow cytometric evaluation of EGFRt transgene expression (grey histograms) on transduced T cells over 10 days of culture in 0.1 µM MTX, 1 µM MPA, or 0.05 µM MTX +0.75 µM MPA. Percentage of positive cells above control staining (open histograms) is indicated in each histogram. (b), Graphical depiction of the percentages of EGFRt⁺ cells shown in (a). Equal numbers of three different gene-modified T cell lines were each plated in a 6-well plate at the indicated drug concentrations. The data represent means ± S.D. There was a significant difference between the cells on D0 vs. D10 at either 0.1 µM MTX, 1 µM MPA, or 0.05 µM MTX +0.75 µM MPA (****, p≤0.0001; *, p≤0.05).