The isolation of a purified plasma membrane fraction from rabbit peritoneal leucocytes by reversible adhesion to nylon fibres

The polymorphonuclear leucocyte (PMN-leucocyte) is a highly motile, phagocytic and secretory cell with a surface membrane responsive to a wide variety of foreign and naturally occurring mediators capable of triggering these processes. Although neutrophil chemotaxis and phagocytosis are fairly well understood phenomena at the descriptive level, the molecular events which take place within the plasma membrane for the receipt and translation of surface signals and the transport processes responsible for the maintenance of a satisfactory intracellular milieu are far from clear. Moreover there is a paucity of information about the extent of the association of cytoskeletal elements with membrane constituents and how these may be involved in the cells’ motile phenomena. To explore the structural and enzymatic basis for the contribution of the PMN-leucocyte plasma membrane to the cells’ functional behaviour, the isolation of a surface membrane free from contamination by intracellular features is a necessary prerequisite. Most current procedures involve some form of mechanical rupture applied to the whole cells, followed by a subcellular fractionation by differential centrifugation or gradient centrifugation in a variety of media [l-4]. In a number of reports using different cell breakage techniques the low enrichment values for surface labels and/or marker enzymes reflect the technical problems in avoiding contamination by intracellular elements in the final plasma membrane preparation