Lecture 12:Innate mechanisms Flashcards
What are the five associations of inflammation
- redness
- swelling
- heat
- pain
- loss of function
What three things does inflammation cause
- vascular permeability
- cellular recruitment
- cellular proliferation and metabolism
What is one of the main roles of inflammation
Bring leukocytes and plasma proteins to a site of infection
What is vascular permeability
- Increased cell and plasma proteins entering the tissue
- increased lymph drainage
What is inflammation overall mediated by?
Cytokines, chemokines and other soluble mediators
What are cytokines
Small proteins released by cells usually in response to a stimulus
What do cytokines do
Induce a response in a target cell by binding to a cytokines receptor
What are the four cytokine families
- interleukins
- hematopoietins
- tumour-necrosis factor
- interferons
What are chemoattractant cytokines
- Cytokines that induce cellular adhesion
- directional cell migration in response to a gradient of the chemokine
Which specific type of receptors do chemokines belong to
Conserved class of 7-transmembrane G-protein coupled receptors
Name the three steps of inflammation
- vasodilation
- increased vascular permeability
- influx of phagocytic leukocytes
When does inflammation occur
- infection
- injury
- organ abnormalities (tumour, stroke)
What are the 4 changes to the vasculature resulting from inflammation
- vascular dilation (blood flow)
- endothelium expression of adhesion molecules
- vascular leakage
- clotting
What is vascular dilation
Increased blood flow
What do adhesion molecules help with
Recruitment of leukocytes
What is vascular leakage
Fluid and plasma proteins (complement and antibodies) enter the tissue (swelling pain)
What is the purpose of clotting in inflammation
Blocks the vessels preventing pathogen spread
What is the local response in the vasculature from inflammation mediated by?
Lipid mediators released from macrophages and neutrophils
Do all soluble mediators act locally
No
What systemic wholistic changes can occur from inflammation
- fever
- increased cellular proliferation and mobilization from the bone marrow
- increased plasma protein production by liver
- mobilization of energy stores (ATP)
Is all inflammation good
No, too much can lead to organ failure and death
What are the fundamental problems with getting innate immune cells to a site of infection
- cells circulate all throughout the body
- cells are flying past spots
- need to get out of blood and into tissue
- leukocytes need to home in on pathogen
How does the endothelium become activated
- detection of pathogen by macrophage or DC cell in tissue
- results in production of cytokines and chemokines
- cytokines and chemokines activate endothelium
- activated endothelium expresses adhesion molecules and additional chemokines
Why don’t all leukocytes get recruited to a site of infection
- differential expression of adhesion molecules
- differential expression of chemokine receptors
