ABSTRACT
Polystyrene latex particles are rapidly phagocytized by rabbit polymorphonuclear (PMN) leukocytes. The uptake is influenced by macromolecules which have the effect of altering the surface charge of the latex particle. The influence of polylysines of varying chain length on the surface charge of latex particles and of PMN cells was studied by micro-electrophoresis. Charge reversal at the latex surface was found to occur at concentrations considerably below that at which the surface charge of the PMN cells is reversed. Phagocytosis of latex by PMN cells is enhanced in the presence of low concentrations of long-chain polylysines. The enhancement of phagocytosis is strongly reduced if PMN cells are treated with neuraminidase. This suggests participation of sialic acid groups in a stage of particle-cell interaction which precedes engulfment.
Subject(s)
Neutrophils/physiology , Phagocytosis , Sialic Acids/physiology , Animals , In Vitro Techniques , Latex , Microspheres , Polylysine/metabolism , Protein Binding , RabbitsABSTRACT
A high-performance liquid chromatographic system was employed to study turnover rates of phospholipids in various types of cells, such as leukocytes, erythrocytes and yeast cells. In the extracts obtained from 32P-labelled cells ten to twelve different phospholipids could be identified. Phosphatidyl glycerol and other minor phospholipids show a high specific activity, so that the lipids may be readily detected. The reproducibility and sensitivity of the method permits the determination of lipid changes during nutrient uptake, phagocytosis, or other cellular activities.
Subject(s)
Phospholipids/metabolism , Animals , Chromatography, High Pressure Liquid , Erythrocytes/metabolism , Humans , Isotope Labeling , Neutrophils/metabolism , Phosphorus Radioisotopes , Rabbits , Saccharomyces cerevisiae/metabolismABSTRACT
Polystyrene latex spherules are rapidly phagocytized by polymorphonuclear leucocytes. Surface modifications of the latex spherules can lead to an inhibition of phagocytosis, and the purpose of this study was to analyse in particular inhibition by bovine and human serum albumin. It can be shown that albumin is bound much more strongly by the PSL particle surface than by the cell surface. Furthermore, a correlation was established between the extent to which the particle surface is covered and the extent of phagocytosis inhibition. In the binding of albumin to the particle surface ionic as well as hydrophobic interactions play a role. As a result, the particle acquires a negatively charged hydrophilic coating which effectively diminishes the number of effective cell-particle collisions leading to engulfment.