NOTCH1 and neoplasm: To explore the mechanism of immunosuppression induced by Notch1 in B16 cells, splenic CD8+ T cells isolated from B16 tumor-bearing mice were expanded and activated with irradiated B16 cells in culture for 3 days prior to test cytotoxic function against B16-shNotch1 or B16-Notch1 cells by chromium release assays.