Figure 3.

Septin filament formation is required for NK cell cytotoxicity. Primary NK (A–E) and NKL (F–H) cells were nucleofected with siCtrl or siRNAs targeting septin 7. Immunoblot is cropped for clarity. (A and F) 48 h (primary NK) and 72 h (NKL) after nucleofection, levels of septin 7 protein were assessed by immunoblot for each experiment. (B and G) Nucleofected cells were incubated at 37°C for 3 h with ⁵¹Cr-labeled 721.221 cells at the indicated Effector:Target (E:T) ratios, and specific lysis was calculated. (C and H) Results were quantified for an E:T ratio of 1.25 effectors to one target cell over six independent experiments. (D) Primary NK cells were incubated with ⁵¹Cr-labeled p815 cells coated with anti-NKG2D + anti-2B4. Percent specific lysis was calculated. (E) Results were quantified at an E:T ratio of 1.25 over four independent experiments. All experiments were completed in triplicate or quadruplicate and in reference to spontaneous and total lysis. Results show representative experiments (left and center; A, B, D, F, and G) or average values over multiple experiments (right; C, E, and H). Error bars indicate SEM. ***, P < 0.0005 compared with control group. P values indicated are for paired, two-tailed Student’s t test. siSept7, siSeptin7.