Modulation of functional activity of human polymorphonuclear and mononuclear phagocytes by intravenous gamma globulin

Intravenous gamma-globulin was tested in a range of concentrations compatible with the increments obtained after therapeutic infusions for modulation of phagocytic functions of human polymorphonuclears (PMNs) and monocytes. Intravenous gammaglobulin in concentrations of 3.0 mg/ml or more increased adhesiveness and suppressed chemotaxis of PMNs. There was marked dose-dependent enhancement of opsonization of gram-positive and gram-negative microorganisms. Preincubation of PMNs with intravenous gamma-globulin caused enhancement of the total bacteria ingested, total bacteria killed, phagocytosis, and phagocytic index, when gram-positive and gram-negative bacteria were tested. During phagocytosis, there was no release of LDH or lysozyme; however, there was release of beta-glucuronidase. No significant difference in phagocytic enhancement was found when filtered and native intravenous gamma-globulin preparations were compared. There was marked enhancement of the superoxide anion generation by intravenous gamma-globulin above the concentration of 0.01 mg/ml. Intravenous gamma-globulin also markedly enhanced phagocytic activity of monocytes. Therefore, intravenous gamma-globulin modulates not only opsonization-related phenomena, but also exerts a complex influence on other aspects of phagocytic activity.