Characteristics of nephritogenic IgA immune complexes.
Studies were undertaken to elucidate the characteristics of IgA immune complexes responsible for glomerular deposition and complement activation. Monomeric IgA antidinitrophenyl (DNP) and the antigen DNP-Ficoll tended to form small soluble complexes that circulated in the blood without localizing in glomeruli of experimental animals. In contrast, polymeric IgA formed intermediate and large-sized complexes that caused glomerular immune deposits. Although covalently cross-linked large-sized IgA oligomers deposited in the glomeruli, they failed to induce concomitant deposition of complement components. Only the presence of a complement-activating antigen endowed the glomerular IgA immune deposits with the ability to activate complement. Thus, the size of the IgA complexes plays a primary role in initiating glomerular localization, and the nature of the antigen causes a secondary phase of inflammation.
Rifai
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Department of Pathology, Rhode Island Hospital, Brown University Medical Program, Providence, RI 02903.
D000818:Animals; D000936:Antigen-Antibody Complex / Q000276:immunology*; D003167:Complement Activation; D005260:Female; D005922:Glomerulonephritis, IGA / Q000276:immunology*; D007070:Immunoglobulin A / Q000276:immunology*; D007678:Kidney Glomerulus / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011108:Polymers
D000936:Antigen-Antibody Complex; D007070:Immunoglobulin A; D011108:Polymers; C034639:polymeric IgA