Innate Immunity Flashcards
What is the immunity system often split into?
- Innate
- Adaptive
What does the immune system entail?
The body’s ability to recognise and defend itself against invaders.
What is the purpose of primary lymphoid tissues?
Educates adaptive immune cells to not recognise itself.
What is the purpose of secondary lymphoid tissues?
Allows adaptive immune cells and antigens to get together to initiate the adaptive immune response.
What is entailed regarding specificity when it comes to the INNATE immune system?
Non - Specific
No memory
What is entailed regarding specificity when it comes to the ADAPTIVE immune system?
Specific
Powerful memory
What are the 3 main types of WBC’s?
Basophils / Eosinophils / Neutrophils
What is the purpose of dendritic cells?
These are messengers between the innate and adaptive immune system.
What are the 4 defensive barriers for innate immunity?
Anatomical / Physiological / Phagocytic / Inflammatory
Name some examples regarding anatomical defensive barriers?
Skin / Mucous Membranes.
Name some examples regarding physiological defensive barriers?
Temperature / Low pH / Chemical Mediators.
Name some examples regarding phagocytic defensive barriers?
Specialised WBC
Name some examples regarding inflammatory defensive barriers?
Releases MANY mediators / Vascular permeability changes / Serum proteins with anti - bacterial activity.
Explain more about the skin as an anatomical barrier.
It’s a mechanical barrier which prevents microbe entry.
Needs an acidic environment in order to prevent growth of microbes.
Explain the mechanism behind bacteria being killed.
Microbe motors are sensitive to pH changes and thus, the pH is lowered.
This means the motor STOPS and thus bacteria is killed.
How is microbe growth stopped?
Chemically interacts with proteins and thus, chemical structure is LOST.
Explain more about mucosal surfaces as an anatomical barrier.
Mucus Entrapment occurs = Protects organs from foreign particles and chemicals.
Cilia Propulsion = Expels bacteria.
What particular social activity can deplete the growth and function of cilia?
Smoking.
Explain more about temperature as a physiological barrier.
37 Celsius degrees.
Inhibits growth and enhance the action of some host enzymes.
Explain more about low pH as a physiological barrier.
Acidity of stomach contents.
Explain more about chemical mediators as a physiological barrier.
Lysozyme / Interferon / Collectins / Proteins are released.
What is collectin and what is the purpose of it?
A combination of collagen and lectin combined.
They are released in order to mediate inflammatory responses.
What are the 3 main processes which occurs with a phagocytic barrier?
- Endocytosis
- Phagocytosis
- Pinocytosis
Explain what endocytosis is?
Uptake of extracellular material.
Explain what phagocytosis is?
Active uptake of particulate material via formation of finger - like projections of cytoplasm and attempted degradation of material.
Explain what pinocytosis is?
Uptake of LARGE soluble material.
What HAS to happen in order for phagocytosis to occur?
The cell has to been in PHYSICAL CONTACT with the particle it wants to engulf in order for phagocytosis to occur.
What happens in direct recognition?
Pattern recognition receptors bind to molecules.
What happens in indirect recognition?
Serum Proteins can coat particles which then are recognised by R’s on the phagocytes.
What are the two pathways which can be taken in order for digestion to occur?
Can be:
- Oxygen Independent
- Oxygen Dependent
In oxygen dependent, why does acidification occur?
Occurs due to lactic acid and H+ being produced.
This results in phagolysosomes becoming acidified.
What are defensins?
These are polypeptides and are electrostatically attracted to pathogens.
They form pores in the surface.
What are the 3 main enzymes present in the oxygen independent pathway?
Lysozyme / Lipase / Proteinase
Explain what is meant by a respiratory burst.
There is a rapid increase in O2 consumption.
Why does the oxygen dependent pathway produce very unstable molecules?
The cytoplasmic and membrane associated enzymes oxidise molecules and thus the molecules are left with unpaired electrons.
Which substances are known as free radicals?
Reactive Oxygen or Nitrogen Intermediates.
List the summary of phagocytosis.
1) Bacterium becomes attached to membrane evaginations called PSEUDOPODIA.
2) Bacterium is ingested = forms a PHAGOSOME.
3) Phagosome fuses with lysosome.
4) Lysosomal enzymes digest captured material.
5) Digestion products are released from the cell.
What is one of the body’s early defence reactions to infection or damage?
Inflammation (this is also known as wide immune activation).
What are the 5 main signs of inflammation?
Rubor = Redness Calor = Heat Dolor = Pain Tumor = Swelling Loss of Function
What events occur during inflammation?
Increasing blood flow / Permeability of vasculature / Limiting infection spread / Tissue damage / Promoting healing.
Name some examples of inflammatory mediators.
Cytokines Enzymatic Cascades Complement Components Prostaglandins Leukotrienes
What are the two categories which cytokines fall into?
Pro - Inflammatory
Anti - Inflammatory
In pro - inflammatory, which interleukins are released early on?
Interleukins - 1,6 and Tumour Necrosis Factor ‘ALPHA’ are released.
These are early alarm signals which produce local and systemic effects.
What is the purpose of Interleukin - 12?
Activates adaptive immune responses within the T- Cells.
What is the purpose of Interferon ‘GAMMA’?
They contribute to the chronic inflammation by recruiting macrophages to sites of damage and infection.
What is the purpose of an anti - inflammatory cytokine?
These dampen the immune response down and is produced MUCH later in the immune response.
What substances are involved with the anti - inflammatory response?
Interleukin 10 and Transforming Growth Factor BETA
What is the purpose of chemokines?
They are small proteins which allow cells to move from one area to another area.
What is another name for chemokines?
Chemoattractants.
What are the two major families of chemokines?
CC and CXC.
What is the process which occurs when specific receptors bind on WBC’s?
Chemotaxis.
Explain what happens during chemotaxis.
Stimulates migration and activation of the cells towards the gradient of the chemokine.
What is a complement (C)?
Group of serum and cell surface proteins.
What is the purpose of a complement?
- Regulate inflammatory and immune responses.
- Act as opsonins to increase phagocytosis.
- Lyse cells and microorganisms.
What are prostaglandins and leukotrienes?
These are unsaturated fatty acids which have been derived from arachidonic acid.
What is the function of prostaglandins?
They cause vascular dilation and enhances the effects of histamine / bradykinin on vascular permeability.
What is the function of leukotrienes?
They promote WBC migration into tissues.
Which two substances increase vascular permeability?
Bradykinin and Plasmin.
Which two substances are known as ‘adhesion molecules?’
VCAM - 1
ICAM - 1
What is the purpose of adhesion molecules?
They bind to monocytes and also, entrap cells to bind.
What is the name of the gap between a NK cell and the target?
An immunological synapse.
What are the 3 main killing mechanisms that the NK cell uses?
- Forms pores in the target cell.
- Induces apoptosis.
- Kills range of tumour targets and virally infected cells.
