PHAGOCYTOSIS-ENHANCING FACTOR IN HUMAN-PLASMA

  • 1 January 1976
    • journal article
    • research article
    • Vol. 30  (6) , 915-924
Abstract
A phagocytosis-enhancing factor (PEF) with the capacity to stimulate the ingestion of sensitized sheep erythrocytes by human polymorphonuclear and mononuclear leukocytes was isolated from human plasma by chromatography on DEAE-cellulose and filtration on Sephadex G-150 and Sephadex G-100. PEF is a protein of approximately 70,000 MW which is susceptible to inactivation by heating at 60.degree. C or by tryptic digestion. PEF promotes phagocytosis of erythrocytes sensitized with intact 7S antibody or bearing C3b [b fragment of the 3rd complement component], but not of unsensitized erythrocytes or erythrocytes sensitized with 19S antibody. The specificity of PEF interaction with target erythrocytes and the persistence of its stimulatory effect after the target cells are washed suggest that it promotes phagocytosis by an action on the erythrocytes.