Uptake of latex particles by macrophages: characterization using flow cytometry

Abstract

Flow cytometry can be used to characterize the uptake of particles by small samples of pulmonary macrophages both quickly and accurately. We found that there was a linear relationship between the number of fluorescent latex particles and the fluorescent intensity associated with each cell up to 47 particles/cell. Macrophages lavaged from the lungs of Syrian golden hamsters were metabolically and functionally stable for 3 h of incubation; the average intracellular concentrations of Na+ and K+ were 29 +/- 2 and 158 +/- 6 mM, respectively. Particle uptake was significantly inhibited by removing divalent cations with ethylenediaminetetraacetic acid and lowering the incubation temperature (37 degrees C) to 24 and 3 degrees C. The cell-to-cell variability in the uptake of particles was greater than the Poisson distribution would predict based on the mean number of particles per cell.