SHAPE OSCILLATIONS OF HUMAN NEUTROPHIL LEUKOCYTES - CHARACTERIZATION AND RELATIONSHIP TO CELL MOTILITY

When neutrophil leukocytes are stimulated by chemotactic factors or by substratum contact, they change their shape. Shape changes are a prer equisite for cellular migration and typically involve the extrusion of thin, veil-like lamellipods and the development of morphological pola rity. Stimulation also leads to changes in the neutrophil content of f ilamentous actin (F-actin), which is the major cytoskeletal component. Suspensions of human neutrophils stimulated with chemoattractants exh ibit sinusoidal lightscattering oscillations with a period of approxim ately 8 s at 37 degrees C. These oscillations arise from periodic fluc tuations in the cell body size caused by lamellipod extension and retr action cycles. The light-scattering oscillations are paralleled by cor responding oscillations in F-actin content. This raises the interestin g possibility that cyclic actin polymerization constitutes the driving force for shape oscillations of suspended neutrophils. Similar period ic shape changes are present in neutrophils crawling on a surface, sug gesting that shape oscillations are important for neutrophil motion. T his review summarizes our present knowledge about shape oscillations i n suspended and crawling neutrophils and discusses a possible role for these oscillations in neutrophil motility.