Diffusive transfer between two intensely interacting cells with limited surface kinetics.

Area of Science:

• Cell Biology
• Immunology
• Biophysics

Background:

• Cell-to-cell communication relies on diffusive transfer, or paracrine delivery, of chemical factors.
• This process is crucial in the cellular immune response, regulating target cell killing, inflammation, and tolerance.
• Understanding paracrine delivery dynamics is key to deciphering cellular interactions.

Purpose of the Study:

• To mathematically model the diffusive transfer of chemical factors between interacting cells.
• To investigate the accumulation and signaling of factors in the intercellular synapse.
• To explore the role of factor accumulation in the activation of naive cells.

Main Methods:

• Solved the steady-state diffusion equation for the concentration field around two interacting cells.
• Incorporated surface kinetics to limit factor emission and absorption rates.
• Presented results in a generic form applicable to various chemical factors and cell types.

Main Results:

• Quantified overall transfer rates and efficiencies of chemical factors between cells.
• Observed significant factor accumulation in the synaptic region when the receiving cell is naive (low receptor density).
• Demonstrated diminished factor accumulation and bystander signaling as the receiving cell becomes more activated and absorbent.

Conclusions:

• Factor accumulation in the cell synapse is critical for activating naive receiving cells.
• The dynamics of paracrine signaling change as cells interact and activate.
• This model provides a framework for understanding intercellular communication in diverse biological contexts.