[Current aspects of chemotaxis of phagocytic cells]

Phagocytic cells, the first host defence against microbial attack, are remarkably mobile; they can move very rapidly to the infectious or inflammatory site. They migrate toward a chemotactic factor: C5a, lymphokines, bacterial products, leukotriene B4, etc. The binding of the chemotactic factor to its specific receptor on the cell leads to an activation of the phagocytic cell: the electric potential of the membrane changes, ionic fluxes and free calcium rate increase, arachidonic acid metabolites are produced, cyclic nucleotides are activated. This produces a change in shape, a polarization of the cell and, after cytoskeleton reorganization, migration of the cell towards the chemotactic factor. A constitutional or acquired abnormality of one of these steps induces a defect of chemotaxis for the phagocytic cells and severe infections.