Innate Immunity Flashcards
What 3 factors determine the outcome of the host-pathogen relationship
One of these factors is lower for 3 groups of people, what are these 3 groups?
Infectivity of pathogen (Ability to establish on/ in the host)
Host’s immune response (Lower for Infants, Elderly, Pregnants)
Virulence (Capability of pathogen to damage host)
What are 4 roles of the immune system
- Pathogen recognition
- Containing/ eliminating the infection
- Regulating itself
- Remembering pathogens
Compare the 2 components of the immune response
Which is most important for human survivial
Innate immunity
- Fast (Seconds)
- Lack of specificity
- Lack of memory
- No intensity change
Adaptive immunity= Most important
- Slow (Days)
- Specific
- Immunologic memory
- Changes in intensity
What are the 4 innate barriers
Physical
Physiological
Chemical
Biological
Name 3 physical barriers
Skin
Mucosal membranes
Bronchial Cilia
Name 4 physiological barriers
Diarrhoea
Vomiting
Coughing
Sneezing
Name 2 chemical barriers
Low pH
Antimicrobial molecules
Name 1 Biological barrier
Where are they absent
Outline 3 benefits
Normal flora is absent in internal organs/ tissues
- Compete with pathogens for resources and attachment sites
- Produce vitamins
- Produce Antimicrobial chemicals
State 6 ways clinical problems start due to Normal flora
- Skin integrity broken
- Fecal oral route
- Fecal perineal urethral route
- Poor dental hygiene/ work
- Normal flora overgrows and becomes pathogenic when host is immuno-compromised
- Normal flora in muscles all surfaces is depleted by antibiotics
What does the spleen do
Protects against microbes in blood
Give 2 examples of Normal flora depletion by antibiotics, that leads to clinical problems
In intestine, Colitis arises from Clostridum Difficile
In vagina, Thrush arises from Candida Albicans
Innate barriers the first lines of defence
What are 2 examples of the second lines of defence
What do they result in
Phagocytes
Chemicals
Inflammation
What do Macrophages release
Cytokines and Chemokines
How are pathogens recognised by phagocytes
PRRs (Pathogen Recognition Receptors) on Phagocytes binds PAMPs on Pathogens
What PRR recognises Lipopolysaccharide (LPS)
TLR4
What are opsonins
Coating proteins that bind to microbial surfaces, leading to enhanced attachment of phagocytes
What does PAMP to PRR binding cause
What does Opsonin to Opsonin receptor binding cause
PAMP-PRR: Signal to produce chemokines and cytokines
O-OR: Causes phagocytosis
Name the 2 phagocyte intracellular killing mechanisms
- Oxygen-dependent pathway (Respiratory burst)
2. Oxygen-independent pathways
What are the actions of complement proteins;
- C3a and C5a
- C3b-C4b
- C5-C9
- Phagocyte recruitment
- Opsonisation of pathogens
- Killing of pathogens, Membrane Attack complex
What 3 functions are carried out by Cyto/ Chemo-kines
- Chemoattraction
- Phagocyte activation
- Inflammation
What Are 3 systemic and 1 local inflammatory actions of the cytokines IL-1, IL-6 and TNF-Alpha
Systemic:
- CRP Released from liver
- Neutrophil mobilisation in bone marrow
- Increased body temp. In hypothalamus
Local:
- Blood vessels dilate, so increased permeability, so attraction of neutrophils as adhesion molecules are expressed
