Paper detail

Close Contact Fluctuations: Time of Contact

The letter resolves the long standing debate as to the proper time scale ($<τ>$) of the onset of the immunological synapse (IS) bond, the non-covalent chemical bond defining the immune pathways involving T-cells and antigen presenting cells (APC). Results from our model calculations show $<τ>$ to be of the order of seconds instead of minutes. Close to the linearly stable regime, we show that in between the two critical spatial thresholds defined by the integrin:ligand pair ($Δ_2\sim$ 40-45 nm) and the T cell receptor (TCR):pMHC bond ($Δ_1\sim$ 14-15 nm), $<τ>$ grows monotonically with increasing co-receptor bond length separation $δ$ (= $Δ_2-Δ_1\sim$ 26-30 nm) while $<τ>$ decays with $Δ_1$ for fixed $Δ_2$. The non-universal $δ$-dependent power-law structure of the probability density function (PDF) further explains why only the TCR:pMHC bond is a likely candidate to form a stable synapse.