Intracellular NK Cell Activation Flow Cytometry Panel

*Designate clones independently validated by HLDA.

This multicolor flow cytometry panel was validated on human peripheral blood mononuclear cells (PBMCs).

Other Supplies Required

• PBS
• Flow Cytometry Staining Buffer (Catalog # FC001)
• Flow Cytometry Fixation Butter (Catalog # FC004)
• Flow Cytometry Permeabilization Buffer/Wash Buffer I (Catalog # FC005)
• Fc-block (blocking IgG)
• (Optional) Isotype Control Antibodies
• 5 mL Flow cytometry tubes

Surface Stain

1. Wash human PBMCs (1 x 10⁶ cells per sample) with 2 mL of Staining Buffer (1X) (Catalog # FC001) or other BSA-containing buffer, by spinning at 300 x g for 5 minutes, using 5 mL flow cytometry tubes. Decant/aspirate supernatant.
2. Fc-block cells with blocking IgG (1 μg IgG/10⁶ cells) for 10 minutes at room temperature.
3. Add 5 μL (or previously titrated amount) of each surface marker (CD3 Alexa Fluor® 405, CD56 Alexa Fluor® 647, and CD16 PerCP). Vortex tubes.
4. (Optional) To a separate tube, add 5 μL of each of the isotype control antibodies. Vortex tubes.
5. Incubate the mixtures for 30-45 minutes at room temperature in the dark.
6. At the end of the incubation, wash with 2 mL of Staining Buffer (1X), by spinning at 300 x g for 5 minutes. Decant/aspirate supernatant.

Intracellular Stain (with detergent permeabilization)

1. Add 0.5 mL of cold Flow Cytometry Fixation Buffer (Catalog # FC004) and vortex. Incubate at room temperature for 10 minutes. Vortex cells intermittently to maintain a single-cell suspension.
2. Centrifuge cells 350-500 x g for 5 minutes. Decant the Fixation Buffer.
3. Wash cells PBS (or HBSS) by adding 2 mL of PBS (or HBSS), centrifuge at 350-500 x g for 5 minutes, and decant buffer from pelleted cells. Repeat (2 total washes).
4. Resuspend the cell pellet in 0.1-0.2 mL of Flow Cytometry Permeabilization Buffer/Wash Buffer I (Catalog # FC005)
   
   Note: Saponin-mediated cell permeabilization is a reversible process, it is important to keep the cells in the presence of Permeabilization Buffer I during intracellular staining. 
   Note: Depending on the specific antibody and cell sample being used, the fixation and permeabilization steps can be performed simultaneously using Flow Cytometry Fixation/Permeabilization Buffer I (Catalog # FC007).
    
5. Add 5-10 µL/10⁶ cells (or a previously titrated amount) of conjugated antibody to intracellular activation markers (Granzyme B Alexa Fluor^® 488, Perforin Alexa Fluor^® 750, and Granzyme K Alexa Fluor^® 594). Vortex tubes.
6. Incubate cells for 30 minutes at room temperature in the dark.
7. Wash cells 2 times with Flow Cytometry Permeabilization Buffer/Wash Buffer I (Catalog # FC005) as described in step 3.
8. Resuspend the cells in 0.2-0.5 mL PBS (or HBSS) buffer and acquire on a Flow Cytometer.