(L20) Innate Immunity Flashcards
What are some of the major barriers created by the innate immunity?
L20 S3-5
- skin
- acidic pH
- mucous epithelium
- ciliated epithelium
What are the hallmark characteristics of inflammation (5)?
L20 S8
- heat
- redness
- swelling
- pain
- loss of function
Why does the body induce inflammation during an infection?
L20 S11
Bloody supply to a region is increased during inflammation, aiding in bringing immune cells to the site. (Redness and warmth)
Vessels become more permeable allowing immune cells and immune plasma proteins to enter the site. (Swelling)
What causes fever?
Is it helpful or harmful to the host?
L20 S12
Fever is induced by the host immune system, not the pathogen!!!
Pyrogenic cytokines (TNF, IL-1, and IL-6) are responsible.
The body does this as pathogens replicate less effectively outside of normal physiologic body temperature.
How do innate immune cells differentiate between self and non-self?
L20 S14
PAMPs (pathogen-associated molecular patterns)
They are factors that are unique to pathogens and not found on host cells.
Typically they are common, constitutively express cell surface molecules that are required for the pathogens
What are examples of PAMPs?
L20 S15
- porin
- certain lipoproteins*
- certain lipopolysaccharides*
- lipoteichoic acid*
- teichoic acid
- mannoprotein*
- β-glycine
- lipoarabinomannan
What are TLRs?
What TLRs are extracellular and which are intracellular and what do they detect?
L20 S17-18
Toll-like receptor, form of PRR (pattern recognition receptor) that detects PAMPs.
Extracellular: (bacterial cell membrane components)
- TLR-1:2 (lipopeptides & GPI (parasites))
- TLR-2:6 (lipoteichoic acid (gram+) and zymosan (fungi))
- TLR-4:4 (LPS (gram-)
- TLR-5 (flagellin)
Intracellular: (bacterial DNA/RNA products)
- TLR-3 (dsRNA
- TLR-7 (ssRNA)
- TLR-8 (ssRNA)
- TLR-9 (CpG DNA)
What signaling pathways do TLRs activate and which TLRs activate each?
L20 S22
MyD88:
- all TLR except TLR3
- TLR4 activates both
TRIF:
- only TLR3 and TLR4
- TLR4 activates both
MyD88 and TRIF are adaptor protein which activate transcription factors NFκB and IRF
What are the results of MyD88 and IRAK-4 deficiencies?
L20 S27
Susceptibility to bacterial and viral infections.
What are NLRs and what is their function?
L20 S28-29
NOD-like receptors
Detect intracellular PAMPs and activate inflammasomes.
Inflammasomes activate caspase-1 which activates precursors of IL-1β and IL-18, pro-inflammatory
What are DAMPs and how are they different from DAMPs?
What are examples?
L20 S32
Damage-associated molecular patterns
Molecules that are released from damaged/dying host cells and activate PRRs on innate immune cells inducing inflammatory response.
Examples (all normally located in the cell hidden from immune cells):
- phosphotidylserine
- HMGB1
- uric acid
- HSP
What autoimmune disease are related to DAMPs?
L20 S37
- MS
- DM
- SLE
- RA
What is fMet and how is it used by the innate immune system?
L20 S40
Constituent of prokaryotes (PAMP) which is recognized by formal peptide receptor.
Used as a chemotatic factor by phagocytes
What are the functions of macrophages?
L20 S41
Detect PAMPs and DAMPs
Mediate extravasation/chemotaxis of other immune cells (inflammation)
Phagocytosis and tissue repair
Release of effector substances (cyto/chemokines, ROS, NO, prostaglandins, and defensins)
Ag presentation to T cells (APC)
Immunomodulation of other immune cells via cytokines
What are the functions of mast cells?
L20 S43-44
Mast cells can be proinflammtory or anti-inflammatory.
Primarily control blood vessel permeability (granule histamine), controlling extravasation of other immune cells.
Frequently primary and rapid response to innate immune triggers in tissues.