Related Experiment Video
Updated: May 14, 2026
09:18
Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death
Published on: December 27, 2016
O death where is thy sting? Immunologic tolerance to apoptotic self
Buvana Ravishankar1, Tracy L McGaha
1Cancer Immunology, Inflammation, and Tolerance Program, GRU Cancer Center, Georgia Regents University, Building CN4143, 1120 15th Street, Augusta, GA, 30904, USA.
Cellular and Molecular Life Sciences : CMLS
|February 5, 2013
Summary
Innate immune cells clear billions of apoptotic cells daily, maintaining homeostasis. Immune tolerance to apoptotic cells is context-dependent, not always immunosuppressive, challenging existing paradigms.
Area of Science:
- Immunology
- Cell Biology
- Homeostasis
Background:
- Innate scavenging cells maintain homeostasis by clearing apoptotic cells.
- Apoptotic cell clearance involves phagocytic cells and signaling pathways for silent removal.
- Understanding molecular mechanisms of immunologic tolerance to apoptotic self is ongoing.
Purpose of the Study:
- Investigate the role of professional phagocytes in initiating immune tolerance.
- Examine how innate immune system perception of apoptotic cells impacts tolerance.
- Challenge the paradigm of inherent immunosuppression by apoptotic cells.
Main Methods:
- Focus on stromal macrophages and CD8α(+)CD103(+) dendritic cells.
- Analysis of alterations in apoptotic cell recognition by the innate immune system.
- Evaluation of consequences of removing phagocytic sentinels or blocking immunosuppressive pathways.
Main Results:
- Professional phagocytes are critical for initiating regulatory cascades leading to immune tolerance.
- Altered apoptotic cell perception by innate immunity causes inflammation and loss of self-tolerance.
- Removal of phagocytic sentinels or blocking immunosuppressive pathways leads to inflammation.
Conclusions:
- Apoptotic cell tolerance is a context-dependent event.
- Apoptotic cells are not inherently immunosuppressive.
- Innate immune system's perception of apoptotic cells is crucial for maintaining self-tolerance.
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...
01:20Special Features of Adaptive Immunity
The adaptive immune system, a crucial component of the overall immune response, offers a highly specialized defense against pathogens. It involves specific cell types and features, enabling it to combat infections effectively and efficiently.
The primary cell types involved in adaptive immunity are T cells and B cells. Each type has a unique role in defending the body against pathogens. T cells are responsible for cell-mediated immunity. They identify and eliminate infected cells directly,...
The primary cell types involved in adaptive immunity are T cells and B cells. Each type has a unique role in defending the body against pathogens. T cells are responsible for cell-mediated immunity. They identify and eliminate infected cells directly,...
01:26Antigens Involved in Adaptive Immunity
An antigen is any substance the immune system identifies as foreign and potentially harmful to the body, prompting an immune response. Antigens have two functional properties: immunogenicity and reactivity. Immunogenicity is the ability of an antigen to stimulate a specific immune response. At the same time, reactivity describes the antigen's ability to react with the cells and antibodies produced in response to it.
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.
01:30Overview of Cell Death
Cell death is an essential process where the body gets rid of old or damaged cells. Cell proliferation and death need to be balanced, as an imbalance between the two may lead to cancer or autoimmune diseases.
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the 20th century...
Cell death was observed in the early 19th century, but there was no experimental evidence to prove it. In 1842, Carl Vogt first discovered cell death in a metamorphic toad; however, it was not termed ‘cell death.’ Scientists discovered different cell death pathways only in the 20th century...
01:40Cell-mediated Immune Responses
Overview