Innate Immune System 2 Flashcards
How long has the innate immune system been around?
~500 million years
What are the professional phagocytes?
macrophages and neutrophils
Complement proteins, professional phagocytes, natural killer cells and dendritic cells make up what?
The innate immune system
What part of the Innate Immune system is also associated with the adaptive immune system?
Dendritic Cells
What is known as the “poor man’s antibodies?”
Complement system
The complement system acts as chemical signals to attract what?
phagocytes
What kind of complexes “poke holes in bad guys?”
membrane attack complexes (MACs)
For the roughly twenty proteins associated with the complement system, what is the primary source that makes the proteins?
Liver
T/F: Proteins are highly concentrated in blood and tissues.
True
What are the three pathways of the complement system that require activation?
Alternative, Lectin, and Classical Pathways
During which pathway of the complement system are complement proteins “spontaneously” activating and attaching to surfaces.
Alternate Pathway
T/F: antibodies are needed for the alternate pathway of the complement system
False; they are not needed.
What are the two parts that C3 will spontaneously split into as part of the alternate pathway?
C3a and C3b
T/F: C3a will either be neutralized by water within 60 microseconds or bind to a pathogen’s surface.
False; these are the possibilities for C3b
What will C3b bind to in the alternative pathway?
amino or hydroxyl groups
What is the most abundant complement protein in the Alternative Pathway?
C3
T/F: C3bBb causes other C3 complement proteins to split, and the result is more C3bBb complement proteins coating the invader.
True
How does C3bBb interact with and activate C5?
by cutting it in half
New C5b combining with other complement proteins (C6, C7, C8, and C9) will result in what?
Membrane Attack Complex (MAC)
What do chemoattractants (C3a and C5a) attract?
macrophages and neutrophils
What do chemoattractants (C3a and C3b) activate?
macrophages and neutrophils
What are the three protection proteins?
MCP, DAF, and Protectin
What does MCP stand for?
membrane cofactor protein
What does MCP do to C3b?
turns C3b into an inactive form
What does DAF stand for?
decay accelerating factor
What does DAF do to convertase (C3bBb)?
accelerates the destruction of convertase
CD59, a cell surface protein is also known as what?
Protectin
How does Protectin protect cells?
removes MACs before they drill holes.
What is the default option of the alternate pathway?
Death: any surface not protected against binding by complement fragments will be targeted for destruction.
What does MBL stand for?
Mannose-binding lectin protein
What pathway is MBL associated with?
Lectin Activation Pathway
Where is MBL primarily produced?
liver
T/F: MBL is present in very high amounts in blood and tissues.
False; MBL is present in moderate amounts in blood and tissues
What activates the Complement System by binding MASP which clips C3 to make C3b?
MBL
What does MASP stand for?
MBL associated serine protein
Lectin is a protein that attaches to what kind of molecule?
carbohydrate
T/F: Mannose is a monosaccharide found on the surface of only parasites.
False; Mannose is found on many pathogens.
What are the two most important professional phagocytes?
macrophages and neutrophils
T/F: Macrophages roam around in blood.
False; macrophages roam around in tissue while neutrophils roam around in blood.
What are the three stages of readiness for macrophages?
Resting, Activated or Primed, and Hyperactive
Which stage of readiness will you find macrophages slowly proliferating and casually eating/snacking?
Resting stage of readiness
What kind of cells do monocytes give rise to?
dendritic cells and macrophages
After monocytes circulate in blood, exit blood, and differentiate in tissues, what kind of cells will they give rise to?
macrophages
During which stage of readiness will macrophages express very few Class II MHCs?
Resting stage of readiness
When will resting macrophages convert to primed macrophages?
after receiving a signal that there are bad guys in the area
T/F: Primed Macrophages express even less Class II MHCs than resting macrophages.
False; many more Class I MHCs are expressed
T/F: Interferon gamma can prime a macrophage.
True
T/F: primed macrophages can produce several complement proteins.
True
T/F: resting macrophages work more with helper T cells than do Primed macrophages.
False; vice versa
T/F: Resting macrophages function much more as an antigen presenting cell than do Primed macrophages.
False; vice versa
What converts a primed macrophage to a hyperactive macrophage?
a direct signal from a bad guy
LPS or Mannose from a bacterial cell wall will do what to a primed macrophage?
convert it to a hyperactive macrophage
At what stage of readiness will macrophages emit cytokines (TNF) and stop proliferating?
Hyperactive
At what stage of readiness will macrophages focus all of their attention on killing and grow large enough to eat whole cells?
Hyperactive
T/F: Hyperactive Macrophages have a decreased number of lysosomes.
False; they have a increased number
T/F: Hyperactive macrophages have an increased production of ROS (reactive oxygen species).
True
What can hyperactive macrophages do to multicellular parasites?
dump their toxic contents onto them.
When is a macrophage considered a garbage collector?
while resting
When is a macrophage considered a vicious killer?
while hyperactivated
When is a macrophage considered an antigen presenting cell and killer?
While activated
T/F: there are about 20 bilion neutrophils in the blood.
True
T/F: Neutrophils present antigens.
False; they do NOT present antigens
Are Neutrophils long lived or short lived?
Short lived (5 days)
After exiting the blood, how long will it take neutrophils to become activated?
about 30 minutes
T/F: neutrophils are active while traveling through the blood.
False; neutrophils activate after they slow down and exit the blood
SEL, SLIG, ICAM, and INT are all what kind of molecules?
Adhesion molecules
What does SEL stand for?
selectin
Where is SEL expressed after receiving alarm signals?
endothelial cells
T/F: SEL binds to SLIG
True
Where is SLIG expressed?
on the surface of neutrophils
What does SLIG stand for?
Selectin ligand
What does ICAM stand for?
intercellular adhesion molecule
Where is ICAM expressed?
on the lumen surface of capillary endothelial cells
What does INT stand for?
Integrin
INT is pre-made and rapidly transported where after being signaled?
the surface of the neutrophil
T/F: INT strongly binds to ICAM.
True
What signal molecules are expressed by macrophages when they are primed or hyperactive that let the neutrophil know a bad guy is present leading to the neutrophil exiting the blood?
IL-1 and TNF
What stimulates capillary endothelial cells to express SEL?
IL-1 and TNF
How long does it take capillary endothelial cells to express SEL?
about 6 hours
T/F: Neutrophils can slow down enough to sense inflammation.
True
What transports INT to its surface?
Neutrophil
What happens to INT after it binds to ICAM?
It stops.
What do C5a and bacterial fragments attract in tissue?
Neutrophils
What special initiator amino acid do all bacterial proteins begin with? Hint: as they ingest bacteria, macrophages burp up these peptides.
formyl methionine (f-met)
Giving off cytokines and forcing cells to commit suicide are the two roles of what cells?
Natural Killer Cells
Where are most NK cells found?
blood, liver and spleen
What is the exit strategy of NK cells for leaving the blood?
Roll, stop, exit strategy
T/F: NK cells are short-lived (one week).
True
T/F: NK cells proliferate slowly.
False, they proliferate rapidly.
Perforin pokes a hole in the membrane like the complement system. Then what?
Injects enzymes that cause the cell to die (apoptosis)
What does the Fas ligand on NK cells bind to on the invader?
Fas protein
What transmembrane protein in the TNF family triggers suicide (apoptosis)?
Fas ligand
What is “cleaner,” apoptosis or necrosis?
apoptosis
What is the “don’t kill” signal present on cell surfaces?
MHC I receptors
What kind of receptors are kill signals?
Activating receptors
What kind of receptors bind the Fc region of IgG?
IgG3 receptors
T/F: Natural killer cells do not have T cell receptors.
True.
What causes the NK cell to kill target (antibody-dependent cellular cytotoxicity)?
IgG3 receptors
T/F: Resting NK cells make more cytokines and are more effective killers than Activated NK cells.
False; vice versa
What growth factor causes NK cells to proliferate when expressing IL-2 receptors?
IL-2
What do the following have in common: a lack of MHCs, LPS, Interferon alpha, Interferon beta, TNF, and IL-12?
they are all signals that activate NK cells
When are interferons usually given off by cells?
When under viral attack
