Opsonic activity of myeloma immunoglobulins (MM-Ig).
Patients with MM are at an increased risk for life-threatening bacterial infections, primarily by organisms that require opsonization for interaction with granulocytes. In the present study we used a neutrophil chemiluminescence (CL) assay of opsonization to explore the opsonic activity of MM-Ig for zymosan particles. Particles were treated with serum lacking in Ig to explore the contribution of Ig to zymosan opsonization. This serum was found to have 69 +/- 2.6% (X +/- SEM) of the opsonic activity of normal serum  (P less than .001). Normal serum concentrations of normal IgG, MM-IgG, and MM-IgA all lacked opsonic activity for zymosan. However, when particles were treated with Nl-IgG, MM-IgG, or MM-IgA as well as complement, normal opsonic activity was generated. Increasing the concentration of the Ig to stimulate MM serum did not inhibit this opsonic activity. Thus both MM-IgG and MM-IgA can function as normal, nonspecific opsonins.
D006098:Granulocytes / Q000276:immunology; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology*; D066298:In Vitro Techniques; D009101:Multiple Myeloma / Q000097:blood / Q000276:immunology*; D009895:Opsonin Proteins / Q000276:immunology*; D010587:Phagocytosis; D015054:Zymosan
D007070:Immunoglobulin A; D007074:Immunoglobulin G; D009895:Opsonin Proteins; D015054:Zymosan