DIFFUSION-MODEL FOR GROWTH-FACTORS CELL RECEPTORS INTERACTION

A theoretical model describing the interaction between growth factor m olecules and their receptors from the cell surface within an 'off-cent re' diffusion approximation is developed in this paper. It is assumed that a number of non interacting particles (growth-factor molecules) m ove diffusively in the presence of traps (specific receptors) which ar e located at the surfaces of a number of cells uniformly distributed i n space. The diffusion equations system is solved by a perturbative me thod. The model predicts a nonlinear dependence of the receptor occupa tion and of the time needed to reach a threshold value of receptor occ upation on the total number of cell receptors. An autocrine binding, w hen the ligand is secreted by the responsive cells accounts for the in teraction between IL-2 and helper T-cells. (C) 1997 Elsevier Science I reland Ltd.