Innate Immune Response Flashcards
Fixed
Innate Immunity
Variable
Adaptive Immunity
Intracellular immune response begins with what:
dendritic cells
Extracellular immune response begins with what:
antibodies, complement/toll-like receptors
What are the cells involved in extracellular immune response?
Macrophages
Dendritic cells
Neutrophils
Spontaneous formation of C3b is in what complement pathway?
Alternative
Complement pathway (classical) starts off by binding to what antibody?
C1 binds to IgM (“landing platform”) which is made by B cells!)
C1 converts:
C2 & C4
C3a is involved with:
C3b is involved with:
C3a = chemotaxis C3b = opsonization
How does C3 become activated?
C2 & C4 complex cleave it into C3a & C3b
C3_ tags bacterium for destruction.
C3b
C3b binds and causes activation of:
C6, C7, C8
C6, C7, C8 bind and cause polymerization of:
C9
C_ polymerizes and forms a pore and pokes a hole in the bacterium.
C9
What initiates the cascade complex?
C5b
What induces phagocytosis of bacterium?
C3b
What are the three major functions of C3b?
1) Opsonin
2) Convertase
3) Activation of B cells (most critical step bc it gives you antibodies)
What are the two inactivating factors for complement?
1) Soluble -> inactivates complement on bacteria & host
2) Membrane bound -> inactivates complement on host
(membrane bound protects our cells from C3b)
(soluble keep amount of C3b under control)
How do you inhibit C1?
C1 inactivating factor - it removes the part that does the cleaving on C1
What are two membrane bound factors that inhibit (alternative) complement?
MCP & DAF -> inhibit ALTERNATIVE pathway
What membrane bound factor inhibits the formation of the pore?
CD59 (binds to C5b, 6, 7, 8 and prevents recruiting of C9)
C3a & C5a are anaphylactoxins. They also:
Alter vascular endothelium & recruit inflammatory cells
What are the four initial steps to extracellular bacteria entering body?
1) Complement activation
2) C3b receptors (for opsonization & B cell activation)
3) C3a & C5a (inflammatory mediators)
4) Cell recruitment
What are four PAMPs?
fMLP, LPS, Glycan, Mannose
- PAMPs are the things that make bacteria cells unique compared to our cells (we don’t have these things!)*
- Our body recognizes PAMPs with TLRs*
What are the cytokines secreted by macrophages? (5)
IL-1 IL-6 IL-12 TNF-a CXCL8 (IL-8) *these are the cytokines of the innate immune response
TNF-a and IL-1 induce:
blood vessels to be more permeable
IL-6 is responsible for changes in:
temperature (it goes to hypothalamus and does this!)
CXCL8 recruits:
neutrophils
What are the 5 principles of cytokine biology? (BRS-FP)
Broad activity Redundant Second messengers Families Pleiotrophic
What are some anti-inflammatory cytokines?
IL-4, IL-10, TGF-B
What are the functions of IL-1 (IL-18)? (ASS-P)
- Activates vascular endothelium & dendritic cells
- Soluble inflammatory mediators
- Systemic effects (causes fever!)
- Produces IFN-y
What are the functions of TNF-a? (ASS-PAC)
- Activates vascular endothelium & dendritic cells
- Soluble inflammatory mediators
- Systemic effects
- Produces IL-1
- Apoptosis
- Collapse venous return (ONLY cytokine that does this!)
IL-1 produces __, and TNF-a produces __.
IL-1 = IFN-y TNF-a = IL-1
The cytokines secreted by macrophages have three major functions, what are they:
1) Activate complement opsonization
2) Phagocytosis
3) Decreased viral & bacterial replication
How does intracellular pathogen process begin?
1) Dendritic cell infected
2) Cytokines are released (IFN-a & IFN-b)
3) Dendritic cells become mature
4) Dendritic cells migrate to lymph node
What are the three major functions of IFN-a and IFN-b?
1) Resist viral replication
2) Increase ligands for receptors in NK cells
3) Activate NK cells to kill infected cells
