A proposal for the definition of terms related to locomotion of leucocytes and other cells.

Abstract

Active locomotion of cells or organisms depends on intrinsic cellular mechanisms which are influenced by factors from the environment. Responses to environmental stimuli which take the form of directed orientation reactions are called taxes; those which take the form of undirected locomotion are called kineses (for review, see I)* The words chemotaxis (2) and chemokinesis (3) may be used to describe such reactions when the stimulus from the environment is chemical. Chemotaxis and chemokinesis play a considerable role in cell locomotion particularly in leucocytes (4, 5 & 6). Analysis of leucocyte locomotion in the presence of a source of a chemical attractant shows that these cells (a) become morphologically oriented in the concentration gradient and (b) migrate directionally towards the source of the gradient (7). Ce.l:Ls exposed to certain chemical stimuli in the absence of a gradient show enhanced locomotion whose speed is determined by the stimulus but which is not directional (8, 9, 10 & 11). It remains to be evaluated whether and to what extent chemotaxis and chemokinesis can be mediated by identical factors. This capacity for active locomotion is a prerequisite for leucocyte emigration into inflammatory sites and influx of these cells into such sites may