Ch 5: Innate Immunity

Question 1

CD47

Answer 1

expressed by young and healthy RBCs to avoid being phagocitized

unfortunately is expressed on human cancer cells

Question 2

What is a common downstream element of TLRs that is often activated upon dimerization with a PRR

Answer 2

NF-kB (a transcription factor)

this is key for inducing many innate and inflammatory genes, including those encoding defensins =

iNOS
chemokine
cytokines (proinflammatory) = TNF-a, IL-1 and IL-6

Question 3

Which downstream element is upregulated upon and interaction of TLR and a viral component

Answer 3

interferon regulatory factors (IRFs)

these are essential for the induction of transcription of the genes encoding IFN-a and b

Question 4

MAPK

Answer 4

a mitogen activated protein kinase

involved in directing cell8ular responses to a diverse array of stimuli such as mitogens, osmotic stress, heat shock and proinflammatory cytokines

Question 5

How is a given signal transduction pathway determined when it comes to TLR// PAMPs

Answer 5

determined by the TLR and the initial protein adaptor that binds to the cytoplasmic domain

this region = TIR domain (from Toll/IL-1 receptor)

Question 6

MyD88 Dependent signaling pathway (cell membrane)

Answer 6

Myloid differentiation factor
post TLR dimer following ligand binding

membrane bound TLRs =2/1, 4 and 5

MyD88 initiates a signalling pathway and activated NF-kB and MAPK pathways by a similar pathway activated by IL-1

Question 7

MyD88 Dependent signaling pathway (endosome)

Answer 7

Myloid differentiation factor

post TLR dimer following ligand binding

endosome bound TLRs = 7, 8 and 9 which bind microbial nucleic acids

triggers pathways that activate IRF7 which induces transcription of IFN-a and b as well as NF-kB and AP-1

Question 8

endosomal TRIF-dependent signaling pathways

Answer 8

TIR domain containing adaptor inducing IFN b factor

TLR 3 and 4 = ds RNA

Trriggers pathways that activate IRF7, IRF3, AP-1 and NF-kB