Figure 4.
Human epidermal growth factor receptor 2 (HER2)-specific T cells secrete immunostimulatory cytokines, proliferate and kill HER2-expressing osteosarcoma cells in coculture. HER2-specific T cells were stimulated with HER2-positive (U2-OS, Sa-OS, SK-ES-1, MNNG, MG-63, HOS, Hs 894, Hs 899, and LM7) or HER2-negative (MDA-MB-468) cells. 24–48-hours poststimulation the (a) IFN-γ and (b) IL-2 concentration was determined. (c) T-cell proliferation was determined by counting viable cells (Trypan blue exclusion) 3 days poststimulation. Only HER2-specific T cells produced IFN-γ and IL-2 and proliferated after exposure to HER2-positive cells in comparison to nontransduced T cells. Results from three experiments from two donors done in duplicates are shown. (d) Only HER2-specific T cells killed HER2 positive osteosarcoma cells, in a 4 hour 51Cr-release cytotoxicity assay; nontransduced (NT) T cells did not. The HER2 negative cell line MDA-MB-468, and HER2-negative fibroblasts, lymphoblastoid B-cell lines (LCL) and T-cell blasts were not killed by HER2-specific or NT T cells. SK-BR-3 was used as a positive control. Results from three experiments done in triplicates are shown.