Intracellular Cytokine Staining
Solutions:
Staining Buffer:
- PBS, pH 7.4-7.6
- 2% heat inactivated BCS
- 0.2% sodium azide
Fixation Buffer (4% paraformaldehyde)
- 14mL 10X PBS
- 10.8mL 37.5% formaldehyde
- 75.2mL dH2O
Perm Buffer
- Staining Buffer + 0.5% saponin
Superperm Buffer
- 3 parts Perm Buffer + 1 part BCS (filtered)
Staining Protocol
After harvesting and any stimulation procedures, incubate cells on ice for 20 minutes. Keep cells on ice until fixation.
- Use a minimum of 1x106 cells per tube
- If necessary, stain for surface markers as per usual FACS protocol
- Wash cells with PBS
- Suspend cells in 0.5mL PBS and 0.5mL fixation buffer. Gently vortex and incubate at room temperature for 20 minutes
- Optional - To store cells after fixation, spin cells down and repeat fixation step, suspend cells in Staining Buffer and store refrigerated for up to 3 days.
- Wash with PBS
All Intracellular Staining steps should be in saponin containing buffers
- Wash with Perm Buffer once and then wash once with Superperm Buffer. After fixation, cells can be vortexed in the usual manner
- Add primary antibody for intracellular staining. It is recommended to use 2x the normal amount that would be used for surface staining, but you may need to optimize by tritration
- Incubate in the dark at room temperature for 30 minutes
- Wash with Perm Buffer twice
- If necessary, add secondary antibody. It is recommended to use 2x the normal amount that would be used for surface staining, but you may need to optimize by tritration. Secondary PE-conjugated reagents are recommended to get the maximum signal.
- Incubate at room temperature for 30 minutes
- Wash with Perm Buffer twice
- Wash with PBS once
- Wash with Staining Buffer once
- Resuspend in 300-500mL Staining Buffer and analyze by FACS
Notes:
- commerical fixative and permiabilization solutions are available if preferred
- Depending on cytokine localization, stronger permeabilizing detergents such as Triton-X or NP-40 may be appropriate (0.1% - 1%)
Adapted From:
- Shimizu Lab/Author Nadine Ottoson http://www.tc.umn.edu/~shimi002/sopicfacs.pdf
- Think Peptides - Intracellular Cytokine Staining http://www.thinkpeptides.com/PR02TP.pdf
- Abcam - Intracellular Staining http://www.abcam.com/ps/pdf/protocols/flow_intracellular_staining.pdf