Lecture 52 Flashcards
(24 cards)
4 main principles of immune responses
Recogniition, response, memory and regulation
How do microorganisms distinguish them from other species?
by expressing unique molecules such as proteins, carbs and lipids
Some microbial molecules are unique to microbes but what? Give an example and what are these called?
But are shared within discrete taxonomic groups.
LPS in gram negative bacteria
Called PAMPs, pathogen associated molecular patterns
Some microbial molecules are unique to a particular organism, give an example and what these are called
Example is those displayed by one strain of influenza virus but not another strain. These are called antigens
Why can some microbes that are normally harmless become pathogenic
Harmless microbes means the immune system was supressed but then expression of these so called harmless microbes, they get turned into pathogens
difference between innate and adaptive immunity
Innate is nonspecific
Adaptive is specific
Describe the various lines of defence for the immunities
1st line of defence for innate is physical, chemical and mechanical barries.
2nd line of defence are cells that kill and defensive molecules - innate
cells that kill, cells that make antibodies, cells that remember and prevent reinfection
Look at featurs of the systems
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Innate immune system controlswhat
early stages of infection
what are the characteristics of innate immune system
Relatively non specific, receptor molecules on cells and in serum recognis PAMPs
Rapid, because components already present
Magnitude constant
Acts as a first line defence
Interacts with and facilitates the adaptive response
What are the fixed and induced defences of innate immunity?
Barries, specialised proteins(complement, chemokines, cytokines) and specialised cells (neutrophils, macrophages, NK cells)
How are these defences activated?
Binding of PAMP by pattern recognition receptors or when anitgens are complexed with antibodies - phagocytes/macrophages
When specialised receptors detect altered self glycoproteins - natural killer CK cells
Epithelial cells are important in innate immunity, more than a physical barrier they also produce what? What is this production induced by?
Produces microbial and inhibitory molecules.
Production is induced by interactions with our normal microbiota
Describe the features of innate and adaptive immune system
1) specificity
2) diversity
3) memory
4) response
5) cellular and chemical barriers
6) blood proteins
7) cells
1) Molecules shared by microbes or damaged host cells - innate
Microbial and non microbial antigens - adaptive
2) llimited and germline encoded - innate
very large; somatic recombination of gene segments - adaptive
3) none - innate
yes - adaptive
4) rapid, constant magnitude - innate
slower, magnitude increases with multiple exposures - adaptive
5) skin, mucosal epithelia, antimicrobial molecules - innate
lymphocytes in epithelia, antibodies secreted at epithelial surfaces - adaptive
6) complement others - innate
antibodies - adaptive
7) phagocytes, NK cells - innate
Lymphocytes - Adaptive
Specialised plasma factors mediating innate immunity recognise what?
recognise pathogen associated molecular patterns PAMPS
What are termed as acute phase proteins and why?
They are rapidly produced in infection.
C-reactive protein, Mannose binding lectin and complement protein.
What are C reactive proteins?
Binds capsule of several bacteria, aids phaocytosis, triggers the complement cascade
What are mannose binding lectin?
Binds mannose residues on pathogens, triggers the complement cascade
What are complement proteins?
Pro enzymes which are triggered after binding a pathogen to produce a cascade of reactions which generate effector molecules against the pathogen
What does the term complement refer to?
To a large group of constitutively produced plasma proteins which interact with pathogens to mark them for killing
What is the critical step in the cascade of proteins once activated?
Breakdown of C3
What are the outcomes of the complement system?
Migration of phagocytes to site of infection.
Pahocytosis of mciroorganisms
Lysis of microorganisms
complement activation involves what?
An enzyme cascade
What does a and b mean for cleaved products of enzyme cascade
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