Related Experiment Video
Updated: Jul 12, 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
Apoptosis driven infection
G van Zandbergen1, W Solbach, T Laskay
1Institute for Medical Microbiology and Hygiene, Centre for Structural and Cell Biology in Medicine, University of Lübeck, Lübeck, Germany. Zandbergen@uni-luebeck.de
Autoimmunity
|May 23, 2007
Summary
Certain pathogens, like Leishmania major, exploit the "eat me" signal phosphatidylserine (PS) to evade immune cells. This allows silent invasion of phagocytes, such as neutrophils and macrophages, establishing infection.
Area of Science:
- Immunology
- Microbiology
- Cell Biology
Background:
- Professional phagocytes, including polymorphonuclear neutrophil granulocytes (PMN) and macrophages (MF), are crucial for pathogen elimination.
- Microorganisms have evolved strategies to evade phagocytic killing and establish infection within host cells.
- Apoptotic cells utilize phosphatidylserine (PS) exposure as an 'eat me' signal, suppressing immune responses during phagocytosis.
Purpose of the Study:
- To investigate the evasion strategies of Leishmania major, a prototypic intracellular pathogen.
- To elucidate how pathogens utilize the apoptotic 'eat me' signal, PS, for host cell invasion.
- To discuss other pathogens employing PS for infection establishment.
Main Methods:
- Focus on Leishmania major as a model organism.
- Analysis of PS exposure by pathogens and infected host cells.
- Observational study of pathogen entry into PMN and MF.
Main Results:
- Leishmania major utilizes PS to silently enter PMN, facilitating the survival of viable parasites.
- Infected PMN expose PS, enabling Leishmania major to silently invade MF, their definitive host cells.
- PS acts as a critical molecular mimicry signal for immune evasion.
Conclusions:
- Leishmania major employs PS-mediated immune silencing for successful infection.
- The apoptotic 'eat me' signal PS is a conserved mechanism exploited by various pathogens.
- Targeting PS-mediated pathways could offer novel therapeutic strategies against intracellular infections.
Related Concept Videos
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...
01:30Apoptosis
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.
01:17The 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...
01:17Phagocytosis 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.
01:18Autophagic 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...
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...