Cryopreserved cytoplasts from human polymorphonuclear leukocytes (cytokineplasts) are chemotactic at speeds comparable to those of fresh intact cells.

Cytokineplasts (CKP) are granule-poor cytoplasts from human polymorphonuclear leukocytes (PMN) that retain motile function, even (unlike the parent PMN) after cryopreservation. Employing time-lapse videomicroscopy, we examined the chemotactic properties of CKP after cryopreservation toward erythrocytes lysed by laser microirradiation. Paths of locomotion were plotted for six CKP in the field, and velocities were calculated at 10-sec intervals. Mean velocities of the six fragments, ranging from 9.3 to 20.8 microns/min, are of the order of fresh, intact PMN, the fastest of locomoting cells.