Shape, motility and locomotor responses of neutrophil granulocytes

Relationships among neutrophil shape, motility and locomotion were analysed. Spherical cells were always non-motile. Two types of motile cells could be distinguished 1) motile polarized neutrophils that were capable of locomotion under conditions of limited adhesion and 2) motile non-polar cells that did not locomote under the same conditions. Polarity appears to be a secondary phenomenon related to locomotion or motility. It can also be reversed, indicating that it is not a characteristic based on fixed cellular structures. The fact that a neutrophil is polarized on the substratum does not provide conclusive evidence of cell motility or locomotion. Neutrophils were found to exhibit orthokinetic but not klinokinetic responses. The speed was mainly or exclusively determined by changes in the proportion of migrating cells. Changes in the speed of the migrating subset play a less important role. Locomotion depends on the activity of the motile apparatus and on adhesion to the substratum. By measuring motility in suspension and adhesion to the substratum the proportion of migrating cells can be predicted. The results show that adhesion and changes in motility play a variable role in chemokinesis. Chemokinetic factors may change only adhesion (example: HSA) or adhesion and the activity of the motile apparatus. The effects of chemokinetic factors on motility and adhesion may be synergistic or antagonistic. The separate assessment of adhesion to the substratum and of motility of floating cells may also be useful for the analysis of biological activities of chemokinetic factors, mechanisms regulating chemokinesis and defects of locomotion.