5% of the total media volume. Our results indicate that this low concentration of DMSO does not significantly alter IFN-γ production compared to assays to which no DMSO was added (data not shown). RT-PCR analysis of IFN-γ transcription.  NK92 effector cells and K562 target cells from some IFN-γ release assays were retained and used to generate cDNA to analyse IFN-γ transcription. Cells

were resuspended in 200 μl RNAStat60 (Ambion, Austin, TX, USA) mixed with chloroform and centrifuged to separate total RNA from cellular debris. Precipitated total RNA was used as RT-PCR template to generate cDNA using Qiagen Omniscript RT Kit (Qiagen, Valencia CA, USA). cDNA was analysed by PCR for IFN-γ expression. GAPDH primers were also used as a control. The primers used were hIFN-γ 109 FP 5′ – ATG AAA TAT ACA AGT TAT ATC TTG GCT TT – 3′ [20] hIFN-γ 474 RP 5′ – CGA ATA ATT AGT ICG-001 manufacturer CAG CTT TTC GAA G – 3′ [21] GAPDH FP 5′ – ATG ACA TCA AGA AGG TGG TG – 3′ GAPDH RP 5′ – CAT ACC AGG AAA TGA GCT TG – 3′ PCR products were analysed by electrophoresis on a 1% agarose

gel with ethidium bromide and visualized by UV fluorescence. IFN-γ PCR product is approximately 370 bp. GAPDH PCR product is approximately 177 bp. Paraformaldehyde fixing.  To prevent the release PD0325901 datasheet of phospho-proteins from K562 when the NK92:K562 cell mixture was subjected to lysis buffer, all K562 target cells were fixed with paraformaldehyde prior to co-incubation with NK92. Published data demonstrates that detergent lysis is prevented by fixing cells in this manner [22–24]. Following the protocol described by Djeu’s Group, K562-CD161 and K562-pCI-neo target cells were resuspended in 4% paraformaldehyde (Fisher Scientific, Pittsburgh, PA, USA) and incubated on ice for 30 min. They were subsequently washed four times with ice cold PBS before being resuspended in an appropriate volume of media for the NK92 co-incubation assay. This paraformaldehyde fixing prevents the detection of K562 intracellular

protein by SDS-PAGE and western blot [22–24]. To confirm that CD161 is still functional after paraformaldehyde fixing, K562-CD161 and K562-pCI-neo fixed target cells were additionally used as target cells for NK92 in overnight Chloroambucil IFN-γ production assays. Phosphorylation assay.  To stimulate phosphorylation of LLT1 downstream signals, NK92 cells that were rested overnight without IL-2 were co-incubated with an equal number of fixed K562 target cells for 5–30 min. Once the incubation was complete, the cell mixture was quickly centrifuged and resuspended in Cell Signalling 1× Cell Lysis Buffer on ice for 5 min. Lysate was then centrifuged for 15 min at maximum speed at 4 °C to remove all cellular debris. Protein levels in supernatants were estimated via spectrophotometry using Bradford reagent to ensure equal loading on SDS-PAGE gels.