title: The capacity of various types of immunoglobulin for intravenous use to interact with Fc receptors of human monocytes and macrophages.
abstract: The capacity of immunoglobulin for intravenous application (IgG-IV) to interact with Fc receptors of human monocytes and macrophages was tested by quantifying the inhibition of phagocytosis of IgG-sensitized erythrocytes. To this end a spectrometric phagocytosis test has been used. When compared with IgG for i.m. use (IgG-IM), all IgG-IV had reduced activity. This reduction was related, in part, to the reduced amount of IgG dimers and polymers in IgG-IV. On a weight basis dimeric IgG and polymeric IgG exerted 6-fold and 14-fold higher activity, respectively, than monomeric IgG. When this difference was corrected for, chemically modified IgG-IV still had significantly reduced inhibitory activity; DEAE-Sephadex-treated IgG and acid-treated IgG had an activity similar to IgG-IM, and PEG-treated IgG showed a slightly reduced activity. Pepsin-treated IgG was greater than 100-fold less active than IgG-IM. The reactivity of IgG-IV with monocyte and macrophage Fc receptors was closely correlated. The most conspicuous differences found were related to the concentration at which IgG was used. Thus, beta-propiolactone-treated IgG and plasmin-treated IgG were found to have significantly reduced activity at concentrations greater than 20 micrograms/ml, but almost normal activity when used at lower concentrations.
mesh_terms: D002478:Cells, Cultured; D006801:Humans; D007116:Immunization, Passive; D007136:Immunoglobulins / Q000008:administration & dosage / Q000276:immunology*; D007275:Injections, Intravenous; D008264:Macrophages / Q000276:immunology*; D009000:Monocytes / Q000276:immunology*; D010587:Phagocytosis; D011961:Receptors, Fc / Q000276:immunology*
chemical_list: D007136:Immunoglobulins; D011961:Receptors, Fc