Chapter 3 Flashcards
Innate immune system uses _______ encoded receptors while adaptive immune system uses antigen receptors of unique specificity assembled from incomplete gene segments during lymphocyte development
germline
Receptors of the innate system are expressed non-clonally. What does this mean?
expressed on all cells of a given cell type
Macrophages have phagocytic receptors that bind __________ and their components
microbes
After entering tissues, many microbes are recognized, ingested, and killed by….
phagocytes
What are the 4 kinds of receptors that facilitate recognition of pathogens?
1) GPCR
2) TLR (toll-like receptor)
3) NLR (NOD-like receptor)
4) RIG (RIG like receptor)
G-protein-coupled receptors (GPCRs) on phagocytes link microbe recognition with increased efficiency of……
intracellular killing
fMet-Leu-Pro
who recognizes this?
GPCR recognizes the fMet of prokaryotes
recognizes that its nonself! only bacteria has fMet
Describe the process of GPCRs on phagocytes that link microbe recognition with increased efficiency of intracellular killing
Activation of Rac and Rho (Rho family small GTPase proteins) helps to increase microbicidal capacity of
_______________ and ____________
macrophages and neutrophils
Activation of fMet and C5a receptors directly allows generation of _____ in phagocytes.
ROS
Respiratory burst is transient increase in oxygen consumption in cell. ROS made and potent killing of
bacteria underway
Neutrophils will secrete what when they arrive to site of infection?
granules
Compare phagocytes to neutrophilic action
Same way in neutrophils:
*Rac 2 activated
*NADPH oxidase activated when phagosome lysosome fuse
*Phagosome fuses with secondary granule
*ROS released
*Ion influx, granules released and digest organism
Neutrophils engulf and kill the microbes to which they bind. Engulfing will openly happens if C3b is on the surface. What happens next?
-bacterial fMet-Leu-Phe peptides activate Rac2, and bacteria are taken up into phagosomes
-phagosomes fuse with primary and secondary granules. Rac2 induces assembly of a functional NADPH oxidase in the phagolysosome membrane, leading ti generation of O2-. Acidification as a result of ion influx releases granule proteases from granule matrix
T/F:
Neutrophils cannot attack extracellular
organisms
false, they can!!!!
Neutrophils can attack extracellular organisms. Nuclear chromatin is released into extracellular spaces
and form a fibril matrix knows as ________________________. These can then be
phagocytosed.
Neutrophil extracellular traps (NETs)
Cytokines produced by macrophages cause dilation of local small blood vessels. What happens now?
-leukocytes move to periphery of blood vessel as a result of increased expression of adhesion molecules by endothelium
-leukocytes extravasate at site of infection
-blood clotting occurs in the microvessels
