L11a: Barrier Immunity And Innate Immunity Flashcards
What is your barrier immunity
First line of defence
What is the barrier immunity
Any part of the body that is exposed to the outside world with a specialised feature to resist pathogen
What does the barrier immunity involve
Physical barrier
Active barrier defence
What is the active barrier defence
Cilia
Secretions
Anti bacterial peptides
What does the barrier of the gut involve
Commensal bacteria
Layers of mucous
Epithelial cells
Paneth cells
What do paneth cells do
Secrete anti microbial peptides
What does the layer of mucous on top of the epithelial cells do
Trap bacteria
What do commensal bacteria do
Barrier and competitor to pathogens
Are commensal bacteria bad/pathogenic
No
When a pathogen breaches the barrier which immune system does it come into contact with first
Innate immune system
Does the innate immune system have memory
No
Does the innate immune system have a high or low specificity
Low
What type of response does the innate immune response produce
Acute phase response/ inflammation
What does the acute phase response involve
Vasodilation
Increased vascular permeability
Cytokines
Nerve stimulation
What does vasodilation cause
Erythema
What does increased vascular permeability cause
Oedema
What does cytokine produce
Heat
What does nerve stimulation cause
Pain
Why is the acute phase response is important
Vasodilation and oedema: allow cells migrate to the tissue
Heat: inhibit pathogen growth
Pain: withdraw from insult
What are the cells of the innate system
Dendritic cells Macrophages Neutrophils Basophils Eosinophil Mast cells
What is the role of dendritic cells and macrophages
Present antigen to cells
What is the role of macrophages and neutrophils
Phagocyte
What is the role of granulocytes i.e neutrophils, eosinophils, mast cells and basophils
Release granules to kill the pathogen
What are macrophages involved in
Detection and phagocytosis of pathogen
What do macrophages originate from
Monocytes
What is the role of dendritic cells
Capture and process antigen into MHC classes to present it to the adaptive immune system
Which cells of the adaptive system does dendritic cells present to
T cells
What are the cells of granulocytes
Neutrophils
Mast cells
Basophils
Eosinophils
Which granulocytes are important for the acute phase response and allergic response
Mast cell
Basophils
What do granulocytes contain
Inflammatory proteins
Toxic enzymes
Oxygen radicals
Which receptors recognise the pathogens
Pattern recognition receptors (PPRs)
Which cells have the pattern recognition receptors (PRRs)
Every innate immune cells
What do PRRs recognise on the microbes
PAMPs
What is the main type of pattern recognition receptor
Toll like receptors
Where are toll like receptors found
On the innate cell surface or inside the cells
What happen when PPR recognise PAMPs
Stimulation of cytokine production
What is the role of cytokine
Attract cells to the site of infection or modulate cell activity
What are the 3 proteins of the innate system
Cytokine
Acute phase proteins
Complement proteins
What is the role of acute phase proteins
Opsonise or present pathogens to the immune system
What is complement
Cascade of proteins that opsonise, kill, activate or chemoattract.
How to cytokines act to stimulate cells
Autocrine
Paracrine
Endocrine
What is autocrine
Acts on the same cell
What is paracrine
Acts on nearby cells
What is endocrine
Acts on distant cells
What are the key cytokine families
Interferon Chemokine Tumour necrosis factor family Interleukin family Haematopoietins Transforming growth factor beta family
Which proteins are involved in opsonisation
Immunoglobulin
Complement
Acute phase proteins
What is opsonisation
Coating the pathogen and making it visible to the immune system
Which cells produce immunoglobulin
B cells
Which marker is used in the hospital setting to see the inflammation
CRP
What happens to the speed of phagocytosis when there is multiple opsonisation via multiple proteins
Faster rate of opsonisation
What is the 3 main ways that we can activate the complement system
Classical
Lectin
Alternative
What is the classical pathway initiated by
Antibody antigen binding
What is the lectin pathway initiated by
Carbohydrates and sugar
What is the alternative pathway initiated by
Direct contact with microbial polysaccharide
What complement protein does all 3 pathways end up activating
C3
What happens when the complement is activated
Inflammation
Cytolysis via MAC (punching a hole in the microbial membrane)
Opsonisation
Chemotaxis: neutrophil attraction by c5a
Inactivation of complement: to limit damage to host cells
Usually where does inactive complement do
Circulate in the blood
