Immune System - Lecture 2 Part A Flashcards
What two types of immunity occur at the same time?
Innate and Adaptive Immunity
What are the three main components of the Innate Response?
- Anatomical or physical barriers
- Chemical barriers
- Cellular responses
What are examples of Anatomical barriers of the Innate response?
- Epithelial layer of skin
* Mucosal tissues of gastrointestinal tract
What is an example of a Chemical Barriers of the Innate response?
Antimicrobial substances produced by the body that help get rid of pathogens
What responses does the body have if a pathogen is able to pass through the anatomical and chemical barriers?
Innate cellular responses
What is the specificity of the Innate Cellular Response?
The innate cellular response is a broad nonspecific response
What does the Innate Cellular Response rely on because it is broad non-specific?
Pattern recognition
What are Patterns in the Innate Cellular Response?
Molecules that are shared among pathogens, that are not specific for a class of pathogens
What does PAMPs stand for and what are they?
Pathogen-associated molecular patterns. They are how the innate response recognizes a pathogen
What form can PAMPs be present in?
- Lipid molecule in the cell wall
* Carbohydrate molecule
Why does the Innate Cellular Response recognize PAMPs that are essential for microbial survival?
Because when pathogens evolve they mutate causing their patterns to change but patterns that are essential for microbial survival usually don’t change so it won’t be able to evade the innate response
What are PAMPs recognized by?
PRRs (Pattern Recognition Receptors)
Where are PRRs that recognize extracellular proteins found?
In the plasma membrane
Why are PRRs also found in endosomes?
So they can recognize pathogens after they have been ingested by cells
Why is it important to have a variety of PRRs?
Because it allows us to amplify our antigen recognition
What recognizes a Pathogen Antigen?
PRRs in or on the cell
What generally happens once a PRR is activated?
An intracellular cascade of events that lead to enhanced protein expression of molecules stimulate adaptive immunity and the inflammatory response
What are Cytokines important for?
Cell communication and stimulation of immune responses
What immune response are stimulated by Cytokines?
Adhesion molecules for white blood cell migration or extravasation for stimulating adaptive immunity
What happens once a Toll-like receptor (type of PRR) recognizes an antigen?
- Transcription factors activated
- Enhance expression of cytokines
- Stimulation of immune response
What are Interferons?
Antiviral chemicals that enhance macrophage activity and send a signal for neighboring cells that viruses are present so they can put in place protective mechanisms
What are Effector mechanisms in the innate immune response?
The mechanisms used by innate cells in order to get rid of pathogens
What are the five main effector mechanisms in the Innate cellular response?
- Anti-microbial substances
- Complement system
- Phagocytosis
- Inflammation
- NK cells
What innate immune response to killing pathogens is Lysozyme a part of?
Anti-microbial substances
Where is Lysozyme present and what does it do?
Tears and Saliva. It is an enzyme that breaks bonds in the cell wall causing cell or pathogen death
Which Innate Cellular Response in Lactoferrin a part of?
Antimicrobial substances
How does Lactoferrin work in the Antimicrobial Innate Cellular Response?
It sequesters iron from the environment and when iron is depleted some microorganisms cannot grow
Where is Lactoferrin found?
In milk and Mucus
Which immune response is Psoriasin a part of?
The Anti-microbial innate cellular immune response
Where is Psoriasin produced and found?
It is a protein produced in the skin
What does Psoriasin do?
Prevents colonization by e.coli
What is the Complement System?
A group of proteins in the innate and adaptive response that help to eliminate pathogens
Where are proteins of the Complement system produced?
The liver
Which immune responses are the Complement proteins considered to be apart of?
The Innate and Adaptive response
What are the seven main categories of the Complement proteins in the Cellular response?
- Initiators
- Convertase activators/enzymatic mediators
- Opsonins
- Anaphylatoxins
- Membrane attack complex (MAC)
- Complement receptors
- Regulatory proteins
What do the Inhibitor Proteins of the Complement Cellular Response mechanism do?
Bind to an antibody that is bound to an antigen and initiate the complement system cascade
What do the Convertase Activators of the Complement system in the Cellular Response do?
Break down complement proteins which activates them in order to activate the next protein in the cascade
What do Opsonins do in the Complement Cellular Response?
Opsonins bind to antigens and stimulate phagocytes to phagocytize
What do Anaphylatoxins do in the Complement immune cellular response system?
They help WBCs migrate to the infection site and are involved in degranulation
What do Membrane Attack Complexes (MAC) do in the Complement Cellular Response?
Form the membrane attack complex which leads to cell death
What do Complement Receptors do in the Complement Cellular Response?
Bind to complement proteins, therefore activating or stimulating actions by the cells that are expressing them
What do Regulatory Proteins do in the Complement Cellular Response?
Prevent exacerbated activation of the complement system so it doesn’t damage the body’s own cells
What are the three main ways to activate the complement system?
- Classical Pathway
- Lectin Pathway
- Alternative Pathway
How is the Classical Pathway in the Complement system activated?
By an antigen antibody complex
How is the Lectin Pathway in the Complement system activated?
By carbohydrate on a cell’s membrane or microbes surfaces
How can the Alternative pathway be activated in the Complement system?
By spontaneous hydrolysis of C3
What do all the activation pathways of the Complement system do?
Convert C3 to C3A and C3B
What is C3A of the complement system involved in?
Inflammation
Why is C3B important in the Complement system?
- It can serve as an Opsonin causing opsonization of antigens
- Clears immune complexes
- Forms C5 convertase
What does it mean for C3B to serve as an Opsonin?
It can bind to a microbe surface and serve as a signal for them to be phagocytosed by a phagocyte
What does it mean for C3B to bind to immune complexes?
It can bind to antigen antibody complexes sending signal causing the microbe to be phagocytized
What occurs when C3B acts as C5 convertase?
It converts C5 to C5B forming the MAC complex forming a pore in the cell membrane killing the cell
Which Complement proteins are involved in MAC formation?
Activation by C3B of C5-C9
Which Complement protein is involved in Opsonization?
C3B
What is Extraversion?
The migration of white blood cells in the complement mechanism to the infected site
Which Complement proteins are involved in Extraversion?
C3A and C5A
What protein is involved in the clearing of immune complexes in the Complement mechanism?
C3B
What are immune complexes?
Antigen and Antibody’s bound together
