Activated macrophages
Definition
Activated macrophages are immune cells that have been stimulated by cytokines to enhance their phagocytic, antimicrobial, and antigen-presenting capabilities. These cells play a critical role in the body's defense mechanisms against pathogens and in inflammatory responses.
5 Must Know Facts For Your Next Test
- Activated macrophages produce higher levels of reactive oxygen species (ROS) and nitric oxide (NO) to kill pathogens.
- They secrete pro-inflammatory cytokines such as TNF-alpha, IL-1, and IL-6.
- Activation typically occurs through exposure to interferon-gamma (IFN-ฮณ) or microbial products like lipopolysaccharides (LPS).
- They present antigens on MHC class II molecules to helper T cells, aiding in the adaptive immune response.
- Chronic activation of macrophages can contribute to tissue damage and is implicated in various autoimmune diseases.
Review Questions
- What are the primary functions of activated macrophages?
- Which cytokines are predominantly involved in the activation of macrophages?
- How do activated macrophages contribute to both pathogen clearance and tissue damage?
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Related terms
Cytokines: Signaling proteins that regulate immunity, inflammation, and hematopoiesis.
Phagocytosis: The process by which cells engulf and digest pathogens or particles.
Antigen-Presenting Cells (APCs): Cells that display antigens on their surface for recognition by T-cells; includes macrophages, dendritic cells, and B-cells.
