A small soluble cluster of bound antigen and antibody. Immune complexes typically contain small antigens, such as toxins or bacterial cell debris, and are commonly found following infections. Generally they are removed from the circulation after triggering the binding of complement proteins, which in turn bind to receptors on red blood cells (erythrocytes). These transport the complexes to the liver and spleen, where macrophages remove the complexes and destroy them, leaving the erythrocytes intact. Failure to remove immune complexes results in their deposition in small blood vessels, particularly of the kidney glomeruli, as occurs in the autoimmune disease systemic lupus erythematosus.
Subjects: Biological Sciences — Medicine and Health.