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31 Cards in this Set

  • Front
  • Back

What is immunology?

The study of the immune system

What is the function of the immune system?

» Defence against infection/foreign materials


» This involves recognition of self/non-self




eg. splinter in your finger - you will get pain and swell, red, and hot. these are signs of inflammation - the body senses this.

Why is the immune system important?

People with impaired immune systems are


more susceptible to microbial disease

What are the two responses of the body?



Innate


Acquired

What is innate response?



AKA non-specific response




It do not depend on prior exposure to foreign material. You get the same response, it does not matter if they were exposed before.


What is acquired response?

It is a response which requires prior exposure to foreign material, are specific, and usually more effective.

What are the components of innate immunity?

• Physical barriers




• Flushing action




• Biological components


» Enzymes


» Phagocytosis


» Complement


» Inflammation




• Nutrient privation




• Microbial competition

What are the physical barrier of the skin?



» Kerratinised epithelia - it is a tough covering


» Mucous membranes - lines the tube and more delicate, easily disrupted and broken


» Connective tissue







What are the components that can disrupt the physical barriers?

- Cuts


- Abrasion eg. dentures


- Burns

What is the function of saliva?

- Washes the microorganisms away from the oral surface of the mouth


- Delivers enzymes and biological components

What is the function of cough/sneeze reflex?

Expels microbes and contaminated secretions

What are the biological enzymes components?

- Lysozyme


- Proteases


- Lipases


- Nucleases

What is the function of lysozyme?

Cleaves the peptidoglycan in bacterial cell wall


(which means it degrades peptidoglycan resulting to weakening of cell wall)



What is the function of proteases?

It breaks down proteins

What is the function of lipases?

It breaks down lipids (fats) eg. membranes

What is the function of nucleases?

It breaks down nucleic acids (RNA and DNA)

Named 3 professional phagocytes?

- Neutrophils


- Macrophages


- Monocytes



Phagocytosis involves?

Phagocytosis involves:


• Adherence of microbe to phagocyte




• Engulfment of microbe into phagosome




• Fusion of lysosomes with phagosome




• Microbial killing:


Oxidative


- Superoxide ion


- Hydrogen peroxide


- Hydroxyl radical


- Hypochlorous radical


Non-oxidative


- Lysozyme


- Myeloperoxidase


- Acid hydrolases




• Release of degradation products

Describe phagocytosis

Describe phagocytosis of fungi

It has a specific uptake system.


Recognition system -


The fungus is recognised by the macrophage through the PAMP (pathogen-associated molecular pattern) which a molecular pattern (green).




The pattern (PAMP) is recognised by the macrophages via PRR (pattern recognition receptor).




With the contact of PAMP and PRR - the macrophage engulfed the fungus.




The engulfed fungus will get in contact with the lysosome and will start secreting enzymes.

What is PAMPs (pathogen-associated molecular patterns)?




Give an example.



Molecules that are part of microbial cells, and not found in human cells, that are recognised by PRR (pattern recognition receptors) and trigger immune defence responses.




eg. B-glucan in the candida albicans cell wall

What is PRRs (pattern recognition receptors)?




Give an example.

Receptor proteins that are found mostly on the surface of immune cells and epithelial cells that bind to PAMPs triggering signals that lead to an immune response




eg. dectin1 which binds to candida albicans B-glucan

What is opsonisation?




What is the advantage in phagocytosis and where can it be found?

Opsonization is a process by which the


efficiency of phagocytosis of foreign materials


by phagocytes is improved.




Antibodies and complement proteins can


opsonize microorganisms - which are then


more readily phagocytosed.




Molecules on the surface of microorganisms


can also act as opsonins that are recognised


by specific phagocyte receptors

What is complement?

Complement is a group of plasma proteins (blood) (C1-C9) that have many functions in the innate and acquired immune response.

What are the functions of complement?

• Enhances phagocytosis of ‘foreign’ material (C3b)




• Lyses Gram-negative bacteria (C5b-9 MAC)




• Promotes chemotaxis (cell migration) in


inflammatory response (C5a)


= this means movement of cells due to the chemical gradient


eg. WBC will migrate into the site of inflammation as they can detect the chemical concentration and they will move towards the higher concentration of C5a protein

What is inflammation?

Inflammation is the process by which components of the immune system are concentrated at a site of infection or tissue damage.

What is the effect of inflammation?

• Increases blood supply to site


• Increases capillary permeability


• A migration of leukocytes (white blood cells) into the tissue (chemotaxis)

Chemotaxis is stimulated by complement proteins. What are the specific types of complement proteins?

C5a, bacterial peptides, and cytokines (eg IL-8)

Describe what happens in the body during the 'acute phase proteins' - also the cause of it and the function.

During an infection, microbial products such as


endotoxins stimulate macrophages to release cytokine interleukin-1 (IL-1).




This increases body temperature and induces the liver to produce ‘acute phase proteins’ such as C-reactive protein (CRP).




CRP ‘fixes’ complement and helps opsonize microbes - increases the attachment of microbes to phagocytes, the first step in phagocytosis.

What is nutrient privation mean?

It means removing nutrients. This is one of the ways that body stops the microorganisms on living by removing the nutrients their need.

How is nutrients privation happening in the body?

High-affinity host iron-binding proteins deprive


microorganisms of iron:


» Transferrin (plasma)


» Lactoferrin (secretions, milk, lysosomes)