SAP-deficient iNKT cells exhibit defective killing of antigen-pulsed target cells in vitro. (A-B) EL4 target cells were pulsed with 100 ng/mL of PBS44 or left untreated (No Ag) and used as targets in an in vitro cytotoxicity assay. Cytolysis of PBS44-loaded or unloaded EL4 cells by iNKT cells from the thymuses (A) or livers (B) of tamoxifen-treated Sapfl/flCre– (SAP+) or Sapfl/flCre+ (SAP−) mice, respectively. (C-D) In vitro cytotoxicity against PBS44-loaded (100 ng/mL) or unloaded A20-CD1d cells by SAP+ or SAP− iNKT cells. In A-D, representative data from 1 of 3 experiments is shown. (E-H) Mean percent reduction ± SEM in cytolysis of antigen-pulsed EL4 (E-F) and A20-CD1d (G-H) cells by SAP− versus SAP+ iNKT cells. Data are averaged from 3 experiments. Statistical significance in percent specific lysis of PBS44-loaded target cells by SAP+ iNKT cells compared with SAP− iNKT cells was determined by two-way analysis of variance (ANOVA) test. **P < .001.
