6 - Induced Innate Immunity Flashcards
What type of cell are Natural Killer (NK) cells?
innate lymphoid cell
What are the 5 genes expressed due to PRR signaling
chemokines (CXCL2) | cytokines | antimicrobial peptides | Type I interferons (IFNa IFNb) | enzymes
What are the 2 key enzymes produced due to PRR signaling?
iNOS and COX2
What is the role of IFNa (alpha) and IFNb (beta)?
binds to IFNa receptor (IFNAR) »_space;> turns on expression of interferon-stimulated genes (ISGs)
What is an example of an IS gene?
PKR (protein kinase R)
What are the 3 major pro-inflammatory cytokines?
IL-1b (or IL-1) | TNFa | IL-6
What are the 4 functions of the 3 major pro-inflammatory cytokines?
increase vascular permeability | induce fever | recruit/activate other leukocytes | induce hematopoiesis = increase neutrophil/myeloid cell production
Why would the pro-inflammatory cytokines want to increase the vascular permeability of the blood vessels?
get more immune cells into circulation »_space;> travel through the vessels »_space;> get to site of infection
Which chemokine will be produced due to PRR signaling?
CXCL2
What is the purpose of CXCL2?
(IL-8) chemoattractant for neutrophils
What is iNOS? What is its purpose?
produces toxic nitric oxide (NO) when activated | causes O2 buildup = targets pathogen to lyse
What is COX2? What is its purpose?
converts lipids to prostaglandins | prostaglandins = inflammatory mediator = more inflammation and fever
What drug targets COX2?
pain killers like acetaminophen
What kind of process is phagocytosis and why?
actin-mediated | needs actin polymerization to occur = pushes membrane forward = moves
What is a phagolysosome? What is its function?
when a phagosome fuses with a lysosome | degrades whatever is in phagosome via lysozome enzymes
What reactive molecule species will aid in degradation and destruction?
reactive oxygen and nitrogen species (ROS) and (RNS)
What are the 4 receptors for phagocytosis?
PRRs | Complement receptors | Opsonins | Fc receptors
What are opsonins?
any kind of protein that will bind on the surface of something (like a pathogen) = basically marks it
What is the complement receptor for macrophages?
CR3
What are the 3 pathways of apoptosis?
apoptosis | neutrophil extracellular traps (NETs) | pyropotosis
What are the 3 ways is apoptosis induced?
TNF binds to TNF-receptor | NK cells | cytotoxic T-cells (CTLs)
How does Neutrophilic Extracellular Traps (NETs) work and relate to apoptosis?
neutrophils phagocytose pathogen = traps them in »_space;> generate NADPH or ROS to induce apoptosis on pathogen and itself
How is pyroptosis induced?
inflammasome activation »_space;> eliminates infected macrophages = releases IL-1b and IL-18
Why is inflammation on site of infection good?
recruits leukocytes to site to kill off pathogens
What are the 4 signs of inflammation in Greek and what do each of the terms mean?
dolor = pain | calor = hot temperature | rudor = redness due to increase in blood flow | tumor = swelling
What induces inflammation?
the 3 key major inflammatory cytokines
Are NK cells activated due to PRR signaling? Why or why not?
No because ILCs lack PRRs = not activated by pathogens
How are NK cells activated?
by cytokines or whatever is in the environment but NOT by pathogens
How do NK cells know which cells to kill? What is significant about the molecule it detects?
kills cells that don’t express MHC class I on surface | MHC class I binds to NK inhibitory receptor = prevents NK killing that cell
Which cells express MHC class I?
all nucleated cells
How would an NK cell know if a cell is virally infected?
viruses target MHC class I expression »_space;> host cell doesn’t express MHC class I »_space;> NK cell inhibitory receptor can’t bind to MHC class I = kills that cell
How do NK cells induce apoptosis on target cell?
perforins and granzymes
