The ability of IgA to inhibit complement consumption by complement-fixing antigens and antigen-antibody complexes.
The polymeric and monomeric (7S) forms of the nitrophenyl-specific MOPC-315 murine IgA myeloma protein were examined for their capacity to inhibit the consumption of guinea-pig complement (C) by the C-activating protein DNP46BSA and by antigen-antibody (Ag-Ab) complexes. On a molar basis, 13S IgA was slightly (2-3 fold) more efficient than 7S IgA in inhibiting C consumption by DNP-BSA. When mixed with IgG antibodies prior to incubation with a non-complement-fixing antigen (TNP-KLH), 13S IgA was considerably more effective than 7S IgA in preventing the formation of Ag-Ab complexes able to fix C. The degree of inhibition observed was related to the concentration of C used in the assay, being greater at lower C concentrations.
D000818:Animals; D000936:Antigen-Antibody Complex / Q000276:immunology*; D003167:Complement Activation / Q000187:drug effects*; D004140:Dinitrophenols; D006168:Guinea Pigs; D006433:Hemocyanins / Q000494:pharmacology; D007070:Immunoglobulin A / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology; D051379:Mice; D009194:Myeloma Proteins / Q000276:immunology; D010851:Picrates / Q000494:pharmacology; D012710:Serum Albumin, Bovine / Q000494:pharmacology*
D000936:Antigen-Antibody Complex; D004140:Dinitrophenols; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D009194:Myeloma Proteins; D010851:Picrates; C034638:dinitrophenyl-bovine serum albumin; C034639:polymeric IgA; D012710:Serum Albumin, Bovine; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin