Analysis of White Blood Cell Deformation

Abstract

In vivo observations in man (1) indicate that compared to red blood cells the leukocyte is relatively stiff and deforms more slowly. Experiments on the flow of leukocytes through tapering glass capillaries (2) and by the use of micropipettes (3,4) quantitatively confirm the impression that white cells deform slowly under a constant stress field. These observations require that any model of the white cell contain a viscous element. Experiments in tapered capillaries (2) and in micropipettes (4) indicate that if a stress is suddenly applied to a white blood cell, it responds with some deformation very rapidly and then continues its slow deformation. These characteristics require that any model also contain an elastic element in series with the viscous element. A model consisting of an elastic element and a fluid element in series is the so-called Maxwell model. Such a model, if deformed and held in a fixed position for sufficient time, would not recover its shape upon release of the stress.