Immunology 3 Flashcards
What are cytokines?
Small ___ ____ that regulate ___, ____, and ____
Produced __ ___ (when ____) in response to ___ ___.
Act over ___ distances and a ___ time span.
Bind to ___ ____ on cells of the immune system
Responses include ___ or ___ in immune cell ____ and ____ out of the ___ and into ____.
Other names for cytokines:
_____
______ (abbreviated IL-1, IL-2, etc)
_____(any cytokine that induces cell _____)
What are cytokines?
Small secreted proteins that regulate immunity, inflammation, and hematopoiesis.
Produced de novo (when needed) in response to immune stimulus.
Act over short distances and a short time span.
Bind to specific receptors on cells of the immune system
Responses include increase or decrease in immune cell proliferation and migration out of the blood and into tissues.
Other names for cytokines:
Lymphokines
Interleukins (abbreviated IL-1, IL-2, etc)
Chemokines (any cytokine that induces cell migration)
Four ways cytokines function
1) ____: ___ cytokine can have ____ different effects
2) _____: ___ cytokines can have the ___ activity
3) ___: _ cytokines working ____ having a ____ effect
4) ____: _ cytokines working___each other.
Four ways cytokines function
1) Pleiotropy: one cytokine can have multiple different effects
2) Redundancy: Multiple cytokines can have the same activity
3) Synergy: 2 cytokines working together having a beneficial effect
4) Antagonism: 2 cytokines working against each other.
Some important cytokines and what they do
- ___ and ___: ___ ___ for __ cells
- Proinflammatory cytokines (promote inflammation):
- ____
- ___
- ___ ___ ___ ___ ___
- ___ ____ ___
- Immunosuppressive cytokines (shut-down inflammation):
- ___
- ___ ___ __ ___ ___
Some important cytokines and what they do
IL-2 and IL-4: growth factors for T cells
Proinflammatory cytokines (promote inflammation):
IL-1β
IL-6
TNFα tumor necrosis factor-α
IFN-γ interferon-γ
Immunosuppressive cytokines (shut-down inflammation):
IL-10
TGFβ transforming growth factor-β
Cytokines produced by Th1 and Th2 Cells and their functions
Cytokines made by Th1: Function to Activate________ immunity
Cytokines made by Th2: Function to Activate_________ immunity
Cytokines produced by Th1 and Th2 Cells and their functions
Cytokines made by Th1: Function to Activate cell-mediated immunity
Cytokines made by Th2: Function to Activate humoral immunity
Cytokines drive B cell _____ and Ig ___ ____
Cytokines drive B cell proliferation and Ig class switching
Interferon-g (IFN-g), a proinflammatory cytokine, enhances the ___ ____activity of _____
An intracellular pathogen infects a macrophage.
Proinflammatory cytokines render the macrophage ____at eliminating the pathogen.
Culture normal or activated macrophages with bacteria in a petri dish.
Fewer bacteria grow in dish with ____ macrophages.
Interferon-g (IFN-g), a proinflammatory cytokine, enhances the anti-microbial activity of macrophages
An intracellular pathogen infects a macrophage.
Proinflammatory cytokines render the macrophage better at eliminating the pathogen.
Culture normal or activated macrophages with bacteria in a petri dish.
Fewer bacteria grow in dish with activated macrophages.
What is Complement and How does it Work?
A family of ___ ____ that work together to attack ___ ____ or destroy ___ ___ cells.
Can be activated by ____ or can act ____ of antibody.
Many components of the complement system contribute to the _____ process, thus making the immune system function more effectively.
Made in____
Present in circulation ___ the ___
What is Complement and How does it Work?
A family of serum proteins that work together to attack extracellular pathogens or destroy infected tissue cells.
Can be activated by antibody or can act independent of antibody.
Many components of the complement system contribute to the inflammatory process, thus making the immune system function more effectively.
Made in liver
Present in circulation all the time
Holes made by complement in the cell membrane allow for ___ ___ to rush ___ causing the cell to ___
Holes made by complement in the cell membrane allow for extracellular fluids to rush in causing the cell to rupture.
The Classical and Alternative Complement Pathways
Three ways the complement system can be activated
___ Pathway
____ Pathway (also an alternative pathway)
____ Pathway
The Classical and Alternative Complement Pathways
Three ways the complement system can be activated
Classical Pathway
Lectin Pathway (also an alternative pathway)
Alternative Pathway
Classical Pathway
When we have a couple of ____ attaching to ____ on the ___ of a ___, the complement cascade will ___ (once it starts it will continue all the way through)
3 molecules called C1q, r and s are activated by ___ and ___
Those 3 molecules become an ___ ___…they have enzymatic activity
Whenever one of these becomes an activated enzyme it will have a line on top of it
Complex is locked in bw antibodies
Enzymes always have a substrate…something that they act on
Substrate is C4 and C2
Part of C4 is chopped off
Part of C2 is chopped off
And we get c4b2a
Pieces left over C2b and C4a
Now we have another enzyme
Next take another component C3
That gets added into the process
3b gets chopped in half by 4b2a
Along comes another complement molecule C5
C5 is chopped. C5a is released and C5b is put into the membrane
All of this is happening on the surface of the cell
Once C5b is there, a couple of molecules just start to fit together.
We get C6 and C7. They get put together with 5b.
C8 (complement 8) gets pulled over with the complex
End up with 5b678
Whole molecule of 5b678 gets surrounded by last complement molecule (C9)
That forms the ___ ___ ____.
Classical Pathway
When we have a couple of antibodies attaching to antigen on the surface of cell, the complement cascade will start (once it starts it will continue all the way through)
3 molecules called C1q, r and s are activated by antigen and antibody.
Those 3 molecules become an active enzyme…they have enzymatic activity
Whenever one of these becomes an activated enzyme it will have a line on top of it
Complex is locked in bw antibodies
Enzymes always have a substrate…something that they act on
Substrate is C4 and C2
Part of C4 is chopped off
Part of C2 is chopped off
And we get c4b2a
Pieces left over C2b and C4a
Now we have another enzyme
Next take another component C3
That gets added into the process
3b gets chopped in half by 4b2a
Along comes another complement molecule C5
C5 is chopped. C5a is released and C5b is put into the membrane
All of this is happening on the surface of the cell
Once C5b is there, a couple of molecules just start to fit together.
We get C6 and C7. They get put together with 5b.
C8 (complement 8) gets pulled over with the complex
End up with 5b678
Whole molecule of 5b678 gets surrounded by last complement molecule (C9)
That forms the Membrane Attack Complex (MAC)
The Alternative Complement Pathway
May be the ___ ____ method for eliminating infectious material because it does not require ____
It can respond ____
The Alternative Complement Pathways Feed into the Complement Cascade at Different Points
Lectin Pathway
- ___ __ ___
- (___ and___)
Alternative Pathway
- ___ ____
- (___)
The Alternative Complement Pathway
May be the most effective method for eliminating infectious material because it does not require antibody.
It can respond immediately.
The Alternative Complement Pathways Feed into the Complement Cascade at Different Points
Lectin Pathway
Microbial Cell Wall
(Glycoproteins and glycolipids)
Alternative Pathway
Microbial Surfaces
(LPS)
Initiators of the Alternative Pathway of Complement Activation
Initiators of the Alternative Pathway of Complement Activation
Gram-positive and gram-negative bacteria
LPS from gram-negative bacteria
Teichoic acid (gram-positive bacteria)
Fungal and yeast cell walls (zymosan)
Some viruses
Some tumor cells
Parasites (trypanosomes)
Biological Effects Mediated by Complement Products of the Complement Cascade
Contribution to the _____ response
- ___ ___ ___ ___
_____of particulate ____, increasing their _____
- ___ ___
Biological Effects Mediated by Complement Products of the Complement Cascade
Contribution to the inflammatory response
C3a, C4a, C5a, C3c
Opsinization of particulate antigens, increasing their phagocytosis
C3b, C4b
Clinical Correlation: Four ways complement contributes to the immune response
- ____: the complement pathway itself
- _____: enhancement of phagocytosis
- ___ of the ___ ___:
- Extravasation: the process of leukocyte ____ out of the ___ into ___ spaces.
- ___ of ___ ____
Clinical Correlation: Four ways complement contributes to the immune response
Lysis is the complement pathway itself
Opsonization: enhancement of phagocytosis
Activation of inflammatory response:
Extravasation: the process of leukocyte migration out of the blood into tissue spaces.
Clearance of immune complexes
Clinical Correlation: The C3b fragment is particularly important for _____ of infectious material.
C3b (and Ab) attach to ____
C3b attaches to ____ on ____
Bacteria are rapidly ___
Clinical Correlation: The C3b fragment is particularly important for opsonization of infectious material.
C3b (and Ab) attach to bacteria.
C3b attaches to receptors on phagocytes.
Bacteria are rapidly engulfed.