Figure 3. Antigen-specific cytotoxicity of T cells expressing engineered-TCRs.

CD8⁺ and CD4⁺ T cells expressing gp100-TCR or SL9-TCR are cytotoxic in a peptide concentration-dependent fashion. Activated CD8⁺ (A) or CD4⁺ (B) T cells ectopically expressing gp100-TCR or SL9-TCR were sorted based on GFP or RFP expression. Sorted cells were cultured with T2 cells plus different peptides at the indicated concentrations. The portion of viable T2 cells was analyzed by FACS after activation, as shown on the Y-axis, whereas the percentage of T cells is shown on the X-axis (A, B). MART-1 (1000 nM) was used as a control. The data are representative from three different experiments from multiple donors. (C) The percent killing of T2 cells (% Cytotoxicity) by CD8⁺ T cells. We calculated % Cytotoxicity by comparing percentage of T2 cell death from peptide-cultured group to those from no peptide control group. The data represent the mean±SD from three different donors. (D) CD8_TCR-SL9 effector cells kill HIV-infected CD4⁺ T cells. HLA-A*0201⁺ CD4⁺ T cells were infected with VSVG.HIV, and were co-cultured with CD8_TCR-SL9 at different CD8⁺: CD4⁺ cell ratios as indicated. The upregulation of CD25 on CD8⁺ T cells (Effector) as well as the % cell death of CD4⁺ T cells (Target), normalized to a CD4-HIV T cell-only group, was determined by FACS analysis. The data are representative from three different experiments from multiple donors.