A STUDY OF THE LEUKOCYTE CHEMOTAXIS IN A GLASS MICROPIPETTE

Chemotaxis, the directional locomotion of a cell toward a source of a chemical gradient, is an important phenomenon occurring for mobilizing immune cells at sites-of infection and injury. This phenomenon has be en modelized in analyzing the movement in vitro of a chemoattracted ce ll inside a glass micropipette. A microneedle filled with fMLP, N-form yl-methionyl-leucyl-phenylalanine, at a concentration of 9.10(-7) M in 1% gelatin, is inserted in a glass micropipette containing Hanks buff er solution. After diffusion of fMLP in the glass micropipette until a constant gradient is established, the tip of the glass micropipette i s moved near a polymorphonuclear neutrophil. Its spontaneous movement inside the micropipette towards the chemotactic source can be observed and quantified. Without any counter-pressure (positive pressure), the cell spontaneously advances with an average velocity of 0.14 +/- 0.04 mu m/s. Corresponding to the maxi mal strength developed by the cell during its motion, the required strength to stop the chemotactic migra tion has been estimated to be 39 +/- 4 nN.Giving both qualitative and quantitative information on the dynamics of cell motility, this experi ment will be helpful in the understanding of some aspects of cell moti lity in the tissues