Inflammatory Cells Flashcards
(25 cards)
what are mast cells?
cellular bags of granules found in large numbers in the skin and linings of the GI and respiratory tract
when are mast cells activated?
physical injury, chemical agents, immunologic and infectious means
what does the activated mast cell synthesize?
inflammatory mediators derived from plasma membrane lipids such as platelet activating factor, prostaglandin D2 and leukotrienes as well as cytokines and growth factors which results in long term response
what is histamine?
is a potent vasodilator that causes increased vascular permeability through retraction of endothelial cells
- also causes smooth muscle to contract causing bronchoconstriction when stimulated in the bronchi
what are leukotrienes?
functions are similar and complementary to that of histamine
- more potent and stimulate slower and more prolonged effects compared to histamine
- cysteine leukotrienes (ex. LCT4, LTD4, LTE4) cause slow and sustained constriction of the bronchioles
what is prostaglandin D2?
causes vasodilation, increased vascular permeability and bronchoconstriction
what are chemotactic chemokines?
are cytokines that attract immune cells, they primarily function to attract leukocytes
what are cytokines?
defined as “small signalling proteins secreted by immune cells that modulate the function of other cells”
- TNF alpha, IL-1, 4, 5, 8, 13)
what are the key mediators in the pathogenesis of asthma?
TNF-alpha, IL-4, 5,8 and 13
what is the function of TNF-alpha?
increased the activation and migration of inflammatory cells (specifically eosinophils and neutrophils) and contributes to airway remodelling
- also causes endothelial cells to express adhesion molecules
what is the function of TNF-alpha and IL-1 together?
alter muscarinic receptor function resulting in increased levels of acetylcholine which causes bronchial smooth muscle contraction and mucus secretion
what are the T helper 2 cytokines?
IL-4, 5, 8 and 13
what is the function of IL-4?
stimulates activation, proliferation and production of antigen-specific, IgE by B cells
what is the function of IL-5?
activates and promotes eosinophils activity
what is the function of IL-8?
causes a more exaggerated inflammatory response through activation of basophils, neutrophils and eosinophils
what is the function of IL-13?
impairs the clearance of mucus, contributes to bronchoconstriction and increases fibroblast secretion
what is the function of PAF (platelet activating factor)?
induces platelet aggregation, increases vascular permeability through endothelial cell retraction, activates neutrophils and is a potent eosinophil chemoattractant
what does PAF cause in the respiratory system?
causes bronchospasm, eosinophil infiltration and non specific bronchial hyperreactivity
what were cysteinyl leukotrienes originally called?
“slow reacting substance of anaphylaxis” due to their effect on bronchial smooth muscle of slow and prolonged contraction and hence bronchoconstriction
what are the leukocytes?
macrophages, eosinophils, neutrophils, lymphocytes and basophils
what are neutrophils, eosinophils and basophils also known as?
granulocytes
which leukocytes are on the scene first and the predominant phagocytes in the early inflammatory phase?
neutrophils
which leukocyte is a T and B cell?
lymphocytes
how are basophils similar to mast cells?
they bind to IgE which is secreted by plasma cells and release histamine and mediators of inflammation such as IL-4
