Silencing SAP or FYN expression in human iNKT cells (hu-iNKT cells) results in reduced cytotoxicity. (A-B) hu-iNKT cells were transfected with control (Ct), SAP-specific (S1 or S2), FYN-specific siRNA (Fyn), or left untransfected (WT). After 72 hours, knockdown of SAP or FYN expression was assessed by immunoblotting. (C-E) Cytolysis of EL4 cells by hu-iNKT cells from three separate healthy controls following transfection with control (Ct), SAP (S1 [C] or S2 [D]), or FYN-specific siRNA (F1 [E]). (F-H) Mean percent reduction ± SEM in cytolysis of EL4 cells by SAP or FYN-silenced hu-iNKT cells compared with control siRNA-transfected cells (S1 [F], S2 [G], and F1 [H]). Data are averaged from 3 donors per condition. Statistical significance in percent specific lysis of PBS44-loaded EL4 cells by SAP- or FYN-silenced hu-iNKT cells compared with control siRNA-transfected cells was determined by two-way ANOVA test. **P < .001.