Comparative study of eosinophil purification on Nycodenz, Metrizamide and Percoll density gradients

Abstract

Studies on the metabolism of human eosinophils and their interaction with helminthic parasites have been hampered by the difficulty in obtaining these granulocytes in sufficient purity and quantity. In this report, we describe for the first time the applicaiton of the density medium Nycodenz for the purificaiton of eosinophis from peripheral blood. Nycodenz density gradients centrifugation is compared with Percoll and Metrizamide gradient centrifugation with special emphasis on cell yield, purity ofcell suspension, and functional integrity ofseparated cells. Percoll gradients provide purer preparations (mean value 94 .+-. 15%) of eosinophils from blood with moderate eosinophilia than Nycodenz or Metrizamide (58 .+-. 29 and 88 .+-. 13%, respectively). The recovery rates of eosinophil-enriched fractions were low after Mycodenz centrifugation (29 .+-. 19%) in comparison to Metrizamide (60 .+-. 21%) or Percoll (70 .+-. 16%). Eosinophils (as neutrophils), prepared by the 3 techniques, function metabolically (suproxide anion generation) and in assays measuring phagocytosis (S. aureus, zymosan particles). Percoll gradient isolated eosinophis (as neutrophils) adhere to and immobilize larvae of Onchocerca volvulus.