J. Phys. III France
Volume 5, Numéro 9, September 1995
Page(s) 1469 - 1480
DOI: 10.1051/jp3:1995204
J. Phys. III France 5 (1995) 1469-1480

The Linear Motor in the Human Neutrophil Migration

V. Vereycken1, H. Gruler2, C. Bucherer1, C. Lacombe1 and J.C. Lelièvre1

1  Unité de Biorhéologie, Université Paris VI et CNRS LBHP URA 343 CHU Pitié-Salpêtrière, 91 bd de l'Hôpital, 75013 Paris, France
2  Chaire scientifique Roger Seydoux de la Fondation de France, Centre d'Ecologie Cellulaire, Groupe Hospitalier Pitié-Salpêtrière, 75651 Paris Cedex 13, France Abteilung Biophysik Universität Ulm, 89069 Ulm, Germany

(Received 13 February 1995, revised 11 May 1995, accepted 25 May 1995)

The kinematics and dynamics of human neutrophils in a narrow glass tube (4.9 $\mu$m to 6.3 $\mu$m in diameter) have been investigated both experimentally and theoretically. Cells were activated by the tri-peptide (fMLP) to migrate through a tube with a mean speed of $0.15\pm 0.03~\mu$m/s (54 activated cells). When a hydrostatic pressure was applied across the cell, the mean speed of the cell leading front linearly decreases when the pressure is increased. At a pressure difference of $1530\pm 140$ Pa (9 activated cells), the cell was forced to stop. The cell migration has been approximated by a tractor-trailer model. The cellular motor (leading front), the tractor, produced a traction force by converting chemical energy into mechanical work. This motor has been characterized as a linear motor with two machine coefficients: (i) the maximum traction T0 (37.7 nN) at V = 0, where  V is the cellular speed (ii) the maximum cellular speed $V_{\rm max}~(0.15~\mu$m/s). A characteristic time of approximately 100 s was measured for the action cycle of the linear motor. A phenomenological description of the chemotactic machine has been presented.

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