FIG. 4.

Human T cells sorted with CD34 mAb demonstrate increased antigen-specific responses. Primary human T cells were transduced with empty virus particles (mock T cells) or with TCR (TCR T cells) or TCR-tCD34 transgenes (TCR-tCD34 T cells) and were either not MACSorted (mock T cells, patterned columns) or MACSorted with Streptamers (TCR T cells, shaded columns; TCR-tCD34 T cells, open columns) or anti-CD34 mAbs (TCR-tCD34 T cells, solid columns). T cells sorted with CD34 mAb show upregulated (A) surface expression of T cell CD107a and (B) IFN-γ production on stimulation with antigen-positive melanoma cells. T cells were stimulated with the following target cells: BLM cells (gp100^–/A2⁺) loaded without or with 10 μM gp100 peptide, and FM3 cells (gp100⁺/A2⁺). CD107a expression (percent) was measured by flow cytometry, gating on viable and CD3-positive T cells, after a 2-hr stimulation, and IFN-γ production (ng/ml) was measured after overnight stimulation with conditioned supernatants by ELISA. Columns and error bars represent mean values and SEM of two independent measurements from two healthy donors. CD107a and IFN-γ data were corrected for differences in peptide–MHC binding, with peptide–MHC binding of CD34 mAb-sorted T cells set to 100% (see Supplementary Fig. S1A for details). Statistically significant differences were calculated by Student t test: *p<0.05; **p<0.005.