Neutrophil chemotaxis: the kinetics of cellular locomotion in vitro.

The Boyden chamber system has been used to study the motile response of rabbit peritoneal neutrophils to partially purified casein cytotaxin. The results of these in vitro experiments indicate that neutrophils respond in two distinct ways to cytotaxin. Firstly, they increase their innate random mobility. Secondly, they respond to the information contained in a cytotaxin concentration gradient by exhibiting directional movement with a velocity vector directed towards the higher cytotaxin concentration. Since the two responses are kinetically distinct, one may infer that they are mechanistically distinct.