301 Immunology Flashcards
What is inflammation?
When blood vessels dilate,
Leading to local swelling and accumulation of components
So TLR activation in epithelium
And activated macrophages contribute by secreting cytokines/chemo lines that attract neutrophils and other cells
Steps on how inflammation takes place
- Bacteria invades tissue
- Bacteria trigger macrophages
- Release cytokines & chemokines
- Bacteria phagocytosed by macrophages
- Chemokines & cytokines move into local blood vessels
- Stimulate vasodilation & increase vascular permeability
- Cause redness, heat & swelling due to blood movement from vessels to peripheral tissue
- Inflammatory cells migrate into tissue and causes pain
What is c5a and what does it do?
Part of innate immune system
Activated again when there is infectious agent
Complement binds to bacterial cell wall & punches hole into cell membrane to kill infecting agent
What are chemokines known as and produced by?
IL8 (interleukin 8)
Monocytes, macrophages, fibroblasts, epithelium and endothelial cells
What are the 2 receptors of chemokines?
CXY R1 and R2
What does CXY R1 and R2 do?
Attract neutrophils and naïve T cells (involved in secondary response)
What is a major effect of IL8?
Mobilises, activates and degranulates neutrophils
Involved in angiogenesis (new blood vessels forming form existing ones)
What is CCL5 released by and what does it attract?
T cells, endothelium and platelets
Monocytes, natural killer cells and T cells, basophuls, neutrophils and dendritic cells
What does CCL5 degranulate and activate?
Basophils
T cells
What is autoimmunity or inflammatory disease (most the time)?
Overproduction of cytokines and chemokines
Triggers/causes of inflammatory disease
Pathogen
Tumours
Autoimmunity
Atherosclerosis (fat build up on artery walls)
Heart disease
Obesity
Any tissue damage (especially chronic)
Why does tissue damage cause inflammatory disease?
Brings immune cells to damage site
Releasing chemokines which bring more immune cells and follow the cycle
Why are Crohn’s and ulcerative colitis ‘technically’ not autoimmune?
Immune cells are attacking commensal gut bacteria instead of own or host cells
Cannot survive without gut bacteria
Cryonic reaction is constant so always inflammatory response
Symptoms of inflammation
Dolor - pain
Rubor - redness
Calor - heat
Turgor - swelling
Monocytes at infection site
- Monocyte binds adhesion molecules on vascular endothelium near infection site, receiving chemokine signal
- Monocyte migrates into surrounding tissue
- Monocyte differentiates into inflammatory monocyte at infection site
Examples of cytokines and chemokines
TNF-α and chemokines
Prostaglandins
Leukotrienes - leukocytes
Platelet activating factor
C5a - complement components + promotion of inflammation
What are cytokines and chemokines?
Messenger molecules that control inflammation, tell immune cells what to do and where to go
Subset of cytokines that direct immune cells to damaged/infected site
Ulcerative colitis
Long term IBD causing colon and rectal inflammation
Crohn’s disease
Chronic IBD can affect entire GI tract from mouth to anus
Describe the molecular inflammatory pathway of Crohn’s disease
- Phagocytes take in bacteria that normally cause no harm but introduce them to macrophages
- Phagocytic cell and macrophage show them as harmful
- Cytokines & chemokines are produced
- Producing Th 1 & Th 17 cells
- Antigen processed by tissue macrophages
- Stimulates helper cells to produce cytokines, chemokines, cytotoxins (cause damage themselves)
Which cytokines & chemokines are produced in immune response to Crohn’s?
IL12, IL6, EGF beta, IL1 beta and IL23