Theory 47/Immunoengineering
T-Cell Activation Is a Spacing Ratio
The claim
T-cell activation is set by the ratio of ligand spacing to receptor size, so the same ligand density can be activating or silent depending on arrangement.
01The mechanism
Receptor clustering requires ligands to be close enough to bridge receptors without steric clash; the ratio of spacing to receptor footprint sets whether clusters form.
02Predictions
- P1Activation should depend on spacing at constant density.
- P2Density alone should mispredict.
03Refutation
Activation tracking density would remove the spacing term.