Methods and theory for analysis of flow of white cell subpopulations through micropore filters

Abstract

Methods have been developed for analysing the resistance of WBC to flow, by measuring their transit rates through 5 and 8 microns pore filters at constant pressure. Unfractionated WBC and separated subpopulations have been compared. For either pore size, lymphocytes exhibited least resistance to flow, followed by granulocytes, with monocytes being most resistant. A theoretical model, which represents WBC suspensions as made up of three particle types (a relatively fast and a relatively slow population, plus a pore blocking population) adequately describes the data for flow rate versus volume filtered. For 5 microns pores, this theory indicates that a majority of WBC have transit times approximately less than 0.5 s. Unfractionated and mixed mononuclear samples contained a proportion of particles with transit times an order of magnitude longer, whereas, for granulocytes, no slow flowing population was evident. Removal of monocytes by plating out, reduced the proportion of the slow particles in the mononuclear preparation. Unique values for transit times could not be determined for 8 microns pores, but it could be concluded that the great majority of WBC made a very quick transit, with the flow becoming dominated by a small number of much more resistant cells. Simple flow parameters (initial relative flow rate and slow particle resistance) are described which characterize these two populations. Both 5 and 8 microns pore data indicated that few cells became permanently trapped within pores.

Effect of mechanical deformation on structure and function of polymorphonuclear leukocytes

“…We have used filters with 3-and 5-µm pore sizes to simulate the smaller 20-30% of pulmonary capillary segments to determine the effect of deformation on the phenotypic and functional characteristics of PMN (5, 16). The experimental procedure chosen to examine the problem has been extensively used by other investigators (6,8,10,11,18,23,27,30), and Selby et al (27) have demonstrated, by using a similar system, a relationship between in vitro deformability of PMN and the in vivo sequestration of radiolabeled PMN in the lungs of human subjects. Downey and Worthen (10) have investigated the factors that deter- Fig.…”

“…To test this hypothesis, we used an in vitro filtration system with polycarbonate membranes to simulate the in vivo mechanical deformation of PMN. This system has been used by others to study the deformability of PMN (6,8,10,11,18,23,27,30), and we have modified it to study the effect of PMN deformation on their structure and function. We measured the deformation that occurs as the cells pass through the polycarbonate filters and assessed cell polarity for evidence of active locomotion.…”

Flow resistance of individual neutrophils in coronary artery disease: decreased pore transit times in acute myocardial infarction.

“…(Heart 1997;77: [18][19][20][21][22][23] Keywords: coronary artery disease; myocardial infarction; reperfusion; leucocytes.…”

Granulocyte Colony-stimulating Factor Induces Neutrophil Sequestration in Rabbit Lungs

“…To investigate the possible mechanisms underlying G-CSF-induced neutrophil sequestration, the effect of pretreatment of rhG-CSF on neutrophil deformability and expression of adhesion molecules (CD11 ր CD18 complex) were studied. Neutrophil deformability was determined by measuring the pressure required to pass neutrophils through a polycarbonate microfilter (20)(21)(22)(23)(24). The surface expression of adhesion molecules was examined by flow cytometry analysis using monoclonal antibodies to CD11a, CD11b, CD11c, and CD18 (25).…”