Nuclear Control
Purpose
The nuclear control answers one question before any reactivity score is interpreted: were viable mast cells present in this test?
A negative result on the titration vial is only meaningful if the nuclear control fired. If the nuclear control also fails to fire, the negative result is invalid — you may have had a bad collection, dead cells, or an assay failure. You don’t know.
This is equivalent to the control line on a lateral flow strip, but actually meaningful — you’re validating cell presence and viability, not just strip function.
What It Is
A maximally potent liberator cocktail that any viable mast cell will respond to regardless of baseline reactivity level. Designed to be a floor, not a ceiling — if cells are alive and present, this fires. No exceptions.
Not measuring MCAS. Not measuring reactivity. Measuring: are there live mast cells here.
Composition (Research/Splatspace Version)
Compound 48/80 at saturating concentration (100µg/mL or above) — direct MRGPRX2 agonist, potent non-IgE liberator.
Calcium ionophore A23187 (optional, strengthens signal) — bypasses receptor entirely, directly triggers calcium influx and degranulation. Belt-and-suspenders with compound 48/80.
Use fume hood when handling compound 48/80 — not acutely hazardous but good practice for any research chemical.
Composition (Consumer Kit Version)
Formulation TBD pending feasibility experiments. Goal: maximally potent liberator combination that is:
- Safe for home use
- Stable in lyophilized or liquid form
- Not a controlled substance or restricted research chemical
Candidates to evaluate: high-concentration citric acid + osmotic shock agent, substance P at saturating concentration, combinations.
Protocol
Take one portion of resuspended cell pellet (from Collection Protocol step 3) and transfer to nuclear control vial.
Wait 10-15 minutes at room temperature.
Expected result if cells present and viable: Clear signal — fluorescence (if using fluorescent substrate), color change (if using colorimetric), or visible degranulation under microscope.
Interpret as:
- Nuclear control fires → cells were present and viable → titration result is valid
- Nuclear control fires slowly or weakly → low cell count, poor viability, or marginal collection → titration result should be interpreted cautiously, consider repeat
- Nuclear control does not fire → invalid test → do not interpret titration result → troubleshoot collection
Relationship to Reactivity Score
The nuclear control and titration vial receive separate portions of the same resuspended pellet. They are run in parallel, not sequentially.
The nuclear control is not a calibration standard for the titration — it is a binary validity gate. It either validates the test or invalidates it. The quantitative information (reactivity score and total burden) comes from the titration vial alone.
Notes
Spontaneous degranulation in nuclear control before liberator is added indicates cells were already partially or fully degranulated at collection — high baseline activation, poor stabilizer effect, or very short time-to-test. Note this and factor into interpretation.
If nuclear control fires immediately upon liberator addition and titration vial also fires early, this is consistent with high reactivity. If nuclear control fires and titration takes many drops, this is consistent with normal reactivity with confirmed cell presence.