Activated CD8⁺ T lymphocytes from K14-β2m mice lyse MHC class I⁺ syngeneic targets in vitro.

(A) Splenocytes from DBA/2, C57BL/6, B6.C-H2^bm1 and K14-β2m mice were stimulated in vitro with irradiated C57BL/6 spleen cells in the presence of exogenous IL-2. After 6 days of culture, effector cells were assayed for cytolytic activity using C57BL/6-derived RMA lymphoma target cells at E/T ratios indicated. Data are representative of 3 independent experiments. Similar results were obtained by using C57BL/6-derived EL-4 thymoma cells as targets (data not shown). (B) In vitro–stimulated effector cells from K14-β2m and B6.C-H2^bm1 mice were incubated for 30 minutes with titrated concentrations of anti-CD4 or anti-CD8 antibodies before addition of labeled RMA target cells. Data are depicted as percentage of lysis in the absence of antibody. (C) Precursor frequency analysis of syngeneic target lysing CD8⁺ T lymphocytes. Indicated numbers of CD8⁺TCRβ⁺ splenocytes were electronically sorted into 96-well plates seeded with C57BL/6 APCs. Lysis of RMA targets was assessed 2 weeks later.