DSA 1,2 Flashcards
Extracellular or Circulating PRRs:
role
examples
- Extracellular, dissolved in plasma, lymphatic fluid, and
interstitial fluids. - Participate as opsonins or in complement (C’) activation
Ex: mannose binding proteins/lectins, pentraxins, C1q
membrane-bound or endosomal PRRs
role
examples
- Expressed on cell surface or in endosomal vesicles.
- Induce expression of cytokines.
- Ex: Toll-like receptors (TLRs), C-type Lectin receptors (CTLRs),
NOD-like receptors (NLRs) - TLRs are the most important class of PRRs
cytosolic PRRs
role
examples
- Found in cytosol, respond to cytosolic bacterial PAMPS,
DAMPS (Damage-Associated Molecular Patterns), and various
RNA species generated during viral replication. - Induce expression of cytokines.
- Ex: MDA-5, RIG-I, NLRs
Pathogen-associated molecular patterns (PAMPs):
examples
- Exogenous signals (“strangers”)- structural features that are essential and broadly conserved among many microbes.
released from infection of pathogen
Ex:
- d-mannose residues (bacteria and fungi)
- n-formyl-methionine-based peptides (bacteria)
- Lipopolysaccharide (LPS, Gram-negative bacteria)
- Lipoteichoic acid (LTA, Gram-positive bacteria)
- Viral RNA, DNA
DAMPS
ex:
Damage-associated molecular pattern (DAMPs):
- Endogenous signals (“dangers”) – components released from
stressed or damaged host cells, alerting immune system of threat and need to clean up.
anything not caused by a pathogen and tissue is under stress
Ex:
- Heat shock protein (chaperone, HSP)
- Mitochondrial DNA
- Extracellular ATP, histones, and uric acid
found in the cells
what is the impostance of opsonins
describe the mechanism of phagocytosis via opsonin-dependent recognition
PAMP-PRR mediated (opsonin-independent) recognition?
pathogens are killed and degraded within the phagolysosome by:
pathways that do not use the oxidative burst use________
Involve hydrolytic enzymes, antimicrobial peptides, defensins, and
lysozyme released from the lysosome upon fusion with the phagosome
(i.e., in the phagolysosome).
what is used during the oxidative burst or respiratory burst?
myeloperoxidase (MPO) deficiency:
deficiency in myeloperoxidase, cant make hypochlorous acid from hydrogen peroxide
Chronic granulomatous disease (CGD):
what are the 2 mechanisms in which pathogens are directly killed cytotoxic factors?
AMP
roles and examples
lysozyme
Mannose-Binding Protein/Lectin (MBP or MBL):
how do they work
where do they bind to and of what?
plasma component
C-reactive protein
function
where does it bind and on what?
Binds to phosphorylcholine on bacteria, viruses, fungi, and protozoan
parasites, as opsonins.
Serum amyloid A protein (SAP)
function
where does it bind and on what?
what are cytokines and examples
what are the complement system receptors
CR1 (CD35) are found on______ and help with
CR2 (CD 21) are found on ______ and help with
C3aR and C5aR (G-coupled protein receptors ) help with
what receptors on macrophages bind to opsonins ?
clinical correlation of complement deficiency?
what type of bacteria are resistant to antibody mediated opsonization? and why is the complement system important here
which complement proteins serve as anaphylatoxins?
what do they cause and where do they bind?
describe the process of cytolysis through the complement system and what happens
what is another function of complement proteins?
invloved in immune complexes (I:C)
