Activation of Innate Immunity Flashcards
(35 cards)
What are the regulatory cytokines and what are they responsible for?
TGF-beta allows repair without regulatory immune cells
IL-10 secreted by macrophages, dendritic cells, and Tregs
What are the endogenous pyrogens?
IL1, IL6, TNF-alpha
What causes SIRS?
Systemic inflammatory response syndrome ==> too many IL1, IL6, TNF-alpha
What causes fever?
Hypothalamic response to IL1, IL6, TNF-alpha
What does fever cause?
- Bacterial and viral replication decreased at higher temperature
- Antigen processing is enhanced
- Adaptive immunity becomes more potent
- Cells become more resistant to TNF-alpha activity by down-regulating receptor
What activates acute-phase proteins?
IL6
What acute-phase proteins are activated in response to infection?
C-reactive protein — binds to phosphorylcholine on bacteria and acts to activate complement and functions as opsonin
Mannose-binding lectin — binds to residues on bacteria; activates complement and acts as opsin
What acts as a non-specific cue for acute inflammation?
C-reactive proteins
What are the the systemic pathologic effects of pyrogens?
Low cardiac output, increased permeability, insulin resistance in multiple tissues
Where is complement produced?
Hepatocytes
Is complement part of innate or adaptive immunity?
Innate
Classical pathway of complement causes what 3 actions?
- Simulates inflammation
- Facilitates antigen phagocytosis
- Can lyse some cells directly
What is the aternative complement pathway called?
Lectin complement
The alternative or lectin C’ pathway begins with…
C3 spontaneous cleavage to C3b and C3a, C3b binds to microbe and acts as an opsin, C3b causes C5 to cleave into C5b and C5a which can lead to MAC
What does MAC stand for?
Membrane attack complex — it creates a pore to cause cell contents to leak
What are the anaphylatoxins and what do they do?
C3a, C4a, C5a and they have inflammatory activity, they are also by-products of complement activation
Induce SM contraction
Induce mast cells/basophils to release inflammatory mediators of histamine and vasodilators which increase capillary permeability
What is the most potent anaphylatoxin?
C5a
What increases the expression of selectins and what do selectins do?
IL1 and TNF, selectins allow luekocyte to roll and eventually stop
What causes integrin to transition to high affinity state?
IL-8
What causes cytoskeletal changes in leukocytes so they can complete extravasation
LFA 1 on neutrophil binding to endothelial ICAM1
How do neutrophils and macrophages eventually find their target?
Chemokine gradient
The acute inflammatory response has 3 steps, what are they?
- Vasodilation (degranulate mast cells, dendritic cells, and macrophages)
- Increased vascular permeability (TNF/IL1/IL6)
- Emigration of leukocytes to site of damage (follow chemokines)
What is the kinin cascade? What does it do?
It is part of the inflammatory response and causes vasodilation, increase permeability of blood vessels, and stimulate pain receptors
What is the fibrinolytic protein?
This degrades the clot when the wound has healed
