Separation of granule subpopulations in human polymorphonuclear leukocytes

Human polymorphonuclear leukocytes were isolated, disrupted by sonification and the nuclei and unbroken cells removed by centrifugation. The supernatant was applied on top of an optimised discontinuous Percoll gradient. After centrifugation we found nine gradient bands of distinct density. Both the nine bands and the whole fractionated gradient material were assayed for granule marker enzymes. Granule fractions of distinct density, enclosing different enzyme concentrations demonstrated the existence of granule subpopulations. There were three subpopulations of azurophil granules, about four subpopulations of specific granules, one granule fraction perhaps representing the C-particles, and a fraction of plasma membrane vesicles.