Related Experiment Video
Updated: May 19, 2026
12:17
Detection and Isolation of Apoptotic Bodies to High Purity
Published on: August 12, 2018
Naturally occurring autoantibodies to apoptotic cells
Keith B Elkon1, Gregg J Silverman
1Department of Medicine and Immunology, University of Washington, Seattle, Washington, USA. elkon@uw.edu
Advances in Experimental Medicine and Biology
|August 21, 2012
Summary
Naturally occurring IgM autoantibodies target dying cells, preventing autoimmunity. These antibodies, particularly anti-phosphorylcholine (PC), reduce inflammation and maintain immune tolerance, crucial for avoiding autoimmune diseases like lupus.
Area of Science:
- Immunology
- Autoimmunity Research
- Lipid Antigen Recognition
Background:
- Naturally occurring IgM autoantibodies (NAbs) recognize cell surface membranes of dying cells.
- These NAbs often target lipid antigens, including phosphorylcholine (PC) and malondialdehyde (MDA).
- The role of IgM NAbs in preventing autoimmune responses and maintaining tolerance is under investigation.
Purpose of the Study:
- To investigate the function of IgM NAbs in recognizing dying cells and their role in immune tolerance.
- To explore the specificities of IgM NAbs against lipid antigens like PC and malondialdehyde (MDA).
- To determine the therapeutic potential of IgM NAbs in inflammatory conditions.
Main Methods:
- Analysis of IgM NAb binding to apoptotic cell membranes.
- Characterization of NAb specificities against lipid antigens (PC, MDA, phospholipids).
- Assessment of complement pathway activation and phagocytosis facilitation by IgM NAbs.
- Evaluation of inflammatory responses in mouse models, including arthritis and lupus-like disease.
Main Results:
- IgM NAbs bind to dying cells, primarily targeting PC and MDA.
- These antibodies activate the classical complement pathway and enhance phagocytosis by antigen-presenting cells.
- Mice lacking serum IgM exhibit a lupus-like disease with IgG autoantibodies.
- IgM anti-PC NAbs demonstrated significant attenuation of inflammation in mouse models of arthritis.
Conclusions:
- IgM NAbs play a critical role in clearing dying cells and preventing autoimmunity.
- IgM antibodies are essential for maintaining immune tolerance and avoiding pathological immune responses.
- Targeting IgM NAbs, such as IgM anti-PC, shows promise for treating inflammatory and autoimmune diseases.
Related Concept Videos
01:17Phagocytosis of Apoptotic Cells
Cells undergoing apoptosis form apoptotic bodies that must be removed immediately to prevent inflammation, autoimmune diseases, and necrosis. Phagocytosis is carried out by professional phagocytes such as macrophages or immature dendritic cells. Non-professional phagocytes such as epithelial cells and fibroblasts also take part in this process; however, they are not as effective as professional phagocytes.
Normal cells contain receptors that prevent them from being recognized by phagocytes.
Normal cells contain receptors that prevent them from being recognized by phagocytes.
01:17The Extrinsic Apoptotic Pathway
The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
01:31The Intrinsic Apoptotic Pathway
Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
01:30Apoptosis
Apoptosis is a combination of two Greek words, 'apo' and 'ptosis,' meaning separation and falling off, respectively. Hippocrates used this word to describe gangrene, which was caused due to bandaging of fractured bones. Apoptosis was distinguished from necrosis in 1970 when John Kerr reported observations of morphological changes occurring during apoptosis. During one experiment, he observed that the disruption of blood supply to the liver tissue resulted in a size reduction of the tissue.
01:22Cellular Injury V: Apoptosis and Autophagy
Cells respond to damage and stress through highly coordinated processes that decide whether they survive or undergo controlled self-destruction. Two major pathways involved in this regulation are apoptosis, a type of programmed cell death, and autophagy, a survival mechanism that helps cells adapt to adverse conditions.ApoptosisApoptosis removes aged or injured cells to maintain tissue balance. During this process, the cell shrinks, chromatin condenses and fragments, and membrane-bound...
01:18Autophagic Cell Death
Christian de Duve discovered “autophagy,” a process in which cellular components are engulfed by membrane-bound organelles called autophagosomes. The autophagosomes then fuse with lysosomes to digest the enclosed contents. Autophagy is generally activated in cells to prevent cell death. However, cell death is triggered when the damage is beyond repair.
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and pro-apoptotic...