Figure 1. p53 expression by melanoma cell lines and stimulation of p53:264 TCR transduced T cells.

Top, PBL from 2 patients (Pt 1, Pt 2) were OKT3 stimulated and left untransduced (Utd) or transduced (Td) on 2 separate days (days 2 and 3) with a MSGV1 based retrovirus encoding the α/β p53_264–272 murine TCR (p53 TCR) resulting in ~50% transduction efficiency. T cells were expanded an additional 5 days in vitro prior to culturing 1 x 10⁵ T cells with 1 x 10⁵ tumor cells overnight. IFN-γ production was determined by ELISA. Bottom, In the same experiment, 1 x 10⁶ tumor cells were assayed for p53 expression by FACS with a PE-labeled mAb specific for mutant and wildtype p53 or isotype control. Both mean fluorescence intensity (MFI p53) and percent of tumor cells (% p53) expressing p53 are shown (both values corrected for the background staining with the isotype control). SaOS2 (HLA-A2⁺p53⁻, osteosarcoma), SaOS2/143 (HLA-A2⁺p53⁺, osteosarcoma line transfected with a mutant p53 gene encoding an amino acid change at position 143), MDA-231 ( HLA-A2⁺p53⁺, breast cancer), and HLA-A2⁻ (1350, 1848) or HLA-A2⁺ (1890, 1833, 2436, 624, 526, 2081, 2098, 2224, 181, 2207, 1994, 2218, and 2319) melanoma cell lines were assayed.