Inflammatory Cells Flashcards
What are 5 acute inflammation effector cells?
- vascular endothelial cells
- neutrophils
- mast cells/basophils
- eosinophils
- monocytes/macrophages
Vascular endothelial cells
Inflammation
- contraction
- release of chemical mediators (NO)
- expression of adhesion molecules and receptors
Leukocytes
- neutrophils
- eosinophil
- basophil/mast cell
- monocyte/macrophage
- lymphocyte/plasma cell
What is the avian equivalent of a neutrophil?
Heterophil
Neutrophil cell characteristics
Segmented nucleus, multiple complex granules
- recruited by IL-8!!
- short lived –> 24 hrs in circulation, 1-2 days in tissue
- aka: polymorphonuclear leukocytes
Neutrophil function
Innate immunity to bacteria and fungi
- phagocytosis
- release of granular contents
What are the 3 phases of neutrophil phagocytosis?
- attachment to particles to the cell surface
- ingestion of particles
- breakdown of particles
_______ greatly facilitates phagocytosis
Opsonization
- via IgG antibodies and complement
Neutrophil granules
- myeloperoxidase: converts H2O to hypochlorous acid which is toxic to microbes
- lysozyme
- antimicrobial substances
- gelatinase: break dwon tissue
Enzymes released cause _____ of the exudate and accumulation of pus
Liquefaction
- **reptiles and birds have reduced concentration of enzymes and cannot liquefy the exudate, leading to formation of caseous material
Neutrophil extracellular traps
Extracellular fibrillary networks that provide high concentrations of antimicrobial substances
- trap microbes to prevent spread
- meshwork of nuclear chromatin that binds and concentrates antimicrobial peptides and enzymes
Neutrophil production and maturation takes place in the _______
Bone marrow
- cytokines stimulate endothelial cells and fibroblasts to produce colony stimulating factors —> CSFs act directly on hematopoietic subpopulations in bone marrow to increase cellular proliferation/differentiation –> release from bone marrow is orderly and age-related with mature segmented cells released first
Eosinophils
1-5% of WBCs
- short lived –> 12 hrs in circulation, 1 week in tissue
- emigrate from blood and live in subepithelial sites in skin, lung, GIT, and endometrium
- enter lesions during transition from acute to chronic inflammation!!!
What attracts eosinophils?
Histamine, eosinophil chemoattractant factor A (mast cells), eotaxin
Eosinophil function
- innate immunity to parasites
- associated with allergies to hypersensitivity
- modulate local immune responses = production and release of cytokines