3 Innate Immune System Flashcards
What is the immune system?
Cells and organs that contribute to immune
defences against infectious and non-infectious
conditions (self vs non-self)
When is a pathogen infectious?
When it succeeds in evading the immune system or overwhelming the host’s immune defences
What are the roles of the immune system?
Pathogen recognition
Containing and eliminating the infection
Regulating itself
Remembering pathogens
List some aspects of innate immunity?
Fast
No specificity
Lack of memory
No change in intensity
What are the different barriers?
Physical barriers
Physiological barriers
Chemical barriers
Biological barriers
What are different physical barriers?
Skin
Mucous membranes
Bronchial cillia
What are the physiological barriers?
Diarrhoea
Vomiting
Coughing
Sneezing
What are the chemical barriers?
Low Ph
Antimicrobial molecules
Name some antimicrobial molecules
IgA Lysozyme Mucus Beta defensins Gastric acid
What areas of the body are kept at low pH?
Skin
Stomach
Vag
What is the role of the normal flora in innate immunity?
Competes for attachment sites and resources and produces antimicrobial chemicals
What molecules do we get from the flora?
Vitamin K
B12
B vitamins
What are some ways that the skin is breached?
Skin loss
Surgery
Injection
IV lines
What sort of person is predisposed to flora overgrowth?
Immuno-compromised
What are the main phagocytes?
Macrophages
Monocytes
Neutrophils
What happens to neutrophil number during infection?
Increases
What cells defends agaisnt multi cellular parasites?
Eosinophils
What cells are early actors in inflammation?
Basophils and mast cells
What PAMP detects LPS?
TLR4
What PAMP detects peptidoglycan?
TLR2
What PAMP detects flagellin?
TLR5
What is oponisation?
Sugar coating, enhances attachment of phagocytes and clearance of microbes
List some opsonins?
C3b C4b IgM IgG CRP MBL
State the phagocytosis pathway
…
What happens in the oxygen dependent pathway?
Toxic O2 products for the pathogens - ROS species
What are the oxygen independent pathways?
Lysozyme
Lactoferrin or transferrin
Cationic proteins
lytic and hydrolytic enzymes
How is the complement pathway activated?
Antibodies
Alternative - cell surface constituents
MBL pathway -
What complement proteins recruit phagocytes?
C3a and C5a
What complement proteins causes opsonisation of pathogens?
C3b and C4b
What complement proteins form the membrane attack complex?
C5 - C9
What chemokines are released by macrophages?
Il-1
IL-6
TNF-a
What the actions of the macrophages derived chemokines?
Increases acute phase proteins
- CRP and MBL
Tell the bone marrow to mobilize neutrophils
Cause inflammatory actions
Tell the hypothalmus to increase the body temperature
