Shreffler:JAX Basophil Activation
Basophil activation in unfractionated samples such as PBMC (note basophils are less dense than Ficoll) or whole blood can be measured by changes in the expression of cell surface markers or even intracellular events (e.g. phosphorylation, oxidative burst, calcium flux) by flow cytometry. Separate markers (e.g. as CD123+ HLA-DR-) are used to specifically identify basophils in addition to those used for assessment of activation.
This protocol is specifically for the JAX study.
- RPMI medium (cellgro, 10-040-CV; store at 4°C in dark)
- IL-3 (R&D) 2 μg/mL
- 1 X FACS lysing solution (made from 10X stock with dH2O; store at 4°C; expires in 1 month)
- PBS + 20 mM EDTA (sterile filter, store at 4°C; expires in 1 month)
- Staining Buffer (PBS + 2 mM EDTA + 0.5% BSA) (sterile filter, store at 4°C; aliquot in hood; expires in 2 months)
- monoclonal antibodies (e.g. CD63-FITC, CD203c-PE, CD123 PE-Cy5, HLA DR-PE-Cy7)
- stimulant aliquots (pre-made, 30 μL aliquots, distributed by Shreffler Lab; stored at -80°C)
- 5 mL round bottom polypropylene tubes (Falcon)
- 1.5 mL eppendorf tubes
- 15 and 50 mL conical tubes
- vacuum filter flasks (Corning #430186)
- pipettes and tips
- serological pipettes (5, 10, 25)
- Obtain whole blood specimens collected in sodium heparin tube (green top). Keep at RT until use (within 16 hours).
- Remove pre-made stimulants (fMLP, Mouse allergen, CaI, PMA, Anti-IgE) from freezer. Label each stimulant and put aside to thaw.
- Record the total volume of blood on the data form.
- Aliquot 5 mL of RPMI into 15 mL conical tube and place it in a 37°C water bath to keep warm (for the dilution of stimulants and for the Unstained Control).
- Label five eppendorf tubes for intermediate CaI/PMA preparation and Mouse 2-5, and eleven 5 mL PP tubes for conditions (A-K).
- Prepare Basophil medium as follows (set aside for step 10):
- Add 4 μL of IL-3 into 2.0 mL of warm RPMI (use 5 mL PP tube). Vortex
- Add 270 μL of warm RPMI to the following stimulants: anti-IgE and fMLP. Pipette up and down to mix in cluster tube.
- Add 135 μL of warm RPMI to each of the Calcium Ionophore and PMA tubes. Transfer both diluted stimulants into a single intermediate 1.5 mL tube labeled CaI/PMA. Vortex
- Prepare 10-fold serial dilutions of the Mouse 1 stimulant as follows:
- Add 270 μL of prepared Basophil medium to Mouse 1 stimulant.
- Transfer 270 μL of the Basophil medium prepared above to each of the Mouse 2-5 eppendorf tubes.
- Transfer 30 μL from Mouse 1 stimulant into Mouse 2 eppendorf, vortex. Repeat this from Mouse 2 eppendorf into Mouse 3 eppendorf and continue making 10-fold dilutions in the same manner until all four Mouse dilutions have been prepared (Mouse 2 –Mouse 5). Vortex after each dilution.
- Transfer 250 μL of warm RPMI into tubes A and B.
- Transfer 250 μL from each of the prepared stimulants above, to the corresponding PP tubes (mouse allergen for tube 'G'; basophil medium for tube 'C').
- IN THE HOOD, add 250 μL of patient blood to all eleven tubes.
- Incubate tubes for 20 minutes in 37°C incubator (5% CO2). Do not shake tubes!
- While incubating, prepare the antibody cocktail and store in 4°C refrigerator until you are ready to use it:
- To 900 uL staining buffer, add 90 μL each of:
- and 12 μL of:
- After 20 minutes of incubation, remove the samples and add 50 μL cold PBS w/ 20 mM EDTA to each tube.
- Add 110 μL of antibody cocktail to tubes B -> K (DO NOT ADD TO A!).
- Incubate for 30 min at 4°C. Protect from light.
- Wash samples with 2 mL staining buffer and centrifuge for 5 minutes at 300g, RT
- Aspirate supernatant, taking care not to disturb cell pellet.
- Add 2 mL of 1x FACS lysing solution. Cover with parafilm and invert repeatedly until pellet is fully resuspended. (An alternative is to add the FACS while tube is on lighter speed vortex. Watch to make sure mixing is thorough; by the time FACS is added to last tube, first tube should be noticeably less opaque.)
- Place tubes in the dark for 15 minutes or overnight in the refrigerator.
- Wash samples with 1.5 mL staining buffer, then centrifuge for 5 minutes at 800g, RT. Decant supernatant and resuspend pellet in 100 μL staining buffer.
- Transfer to 1.5 mL eppendorf tube and seal with parafilm for shipping.
- Ship to Shreffler Lab at room temperature.
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- Who has experience with this protocol?
- Email Wayne Shreffler through OpenWetWare