Description of cell adhesion by the langmuir adsorption isotherm

The adhesion of granulocytes to a glass surface is both theoretically and experimentally investigated. The basic results are: (i) The adherence process of cells to a surface can be described by the Langmuir adsorption isotherm which also holds for the adsorption of molecules to a substrate. (ii) The granulocytes do not interact with each other during the adsorption/desorption process. (iii) The equilibrium constant at 37 degrees C for granulocytes adsorption to the glass surface is 170 cells/mm3 = 1.7 x 10(5) cells/ml. (iv) The equilibrium constant increases with decreasing temperature. (v) The equilibrium constant is a function of the chemokinetic/chemotactic stimulus f-Met-Leu-Phe. (vi) The desorption rate is also a function of the chemokinetic/chemotactic stimulus (kde-1 = 71.5 min for 1 nM and 330 min for 1 microM f-Met-Leu-Phe). (vii) The adsorption rate is a function of the chemokinetic/chemotactic stimulus and the cellular bulk concentration (kad-1.cv-1 = 104 min for 1 nM and 8 min for 1 microM f-Met-Leu-Phe, and cV = 4000 cells/mm3 = 4 x 10(6) cells/ml). (viii) The total number of cells which can bind to the surface is independent of temperature (and of the chemokinetic/chemotactic stimulus). (ix) The high affinity receptor site is responsible for the adherence (Kf-Met- = 1.8 nM f-Met-Leu-Phe). (x) The chemokinetic/chemotactic stimulated adherence is a cooperative process on a molecular level. (xi) The cellular adsorption/desorption process is a rate controlled process. The thermodynamic description of the adsorption/desorption process failed.