Cytokines and TLR Quiz

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Questions and Answers

What is a major function of cytokines, according to the provided text?

Stimulation of growth

What type of cells can release cytokines, based on the information provided?

All cells

What is the role of caspases in relation to cytokines?

They cleave cytokines

What is the effect of macrophage colony factor on bone marrow, as described?

Stimulation Signup and view all the answers

Where are cytokines found after being cleaved by caspases?

extracellular Signup and view all the answers

What does PRR stand for, as mentioned in the context?

Pattern Recognition Receptor Signup and view all the answers

What do many PRRs recognize?

Ligands Signup and view all the answers

What part of the TLR faces the cytosol?

C-term Signup and view all the answers

How many different TLRs are mentioned in the text?

10 Signup and view all the answers

Which TLR is specifically mentioned to recognize Lipid A?

TLR4 Signup and view all the answers

What is the name of the protein that resides with TLR4 in the plasma membrane?

MDL Signup and view all the answers

Which TLR recognizes lipoteichoic acids and lipoproteins?

TLR2 Signup and view all the answers

What type of molecule is Lipopolysaccharide (LPS), as related to TLR4?

sugar Signup and view all the answers

What type of molecules do TLR 3/7/8 recognize?

Viral RNAs, specifically double-stranded RNAs. Signup and view all the answers

What is the primary function of the acyl group as depicted?

The primary function of the acyl group is to stabilize the binding of the TLR. Signup and view all the answers

What is the specific structural feature that TLR9 recognizes in microbial DNAs?

TLR9 recognizes unmethylated cytosine-guanine dinucleotide (CpG) motifs. Signup and view all the answers

Where are TLR 3/7/8 located within the cell?

They are located in the endosomal compartment. Signup and view all the answers

What is the significance of dimerization in the context of TLR activation?

Dimerization is necessary to initiate the activation signal. Signup and view all the answers

What type of RNA is most important for binding to TLR 3/7/8?

Double-stranded RNA is the most important ligand. Signup and view all the answers

What is the primary role of TLRs in initiating an immune response?

TLRs recognize viral or bacterial components and initiate signaling cascades. Signup and view all the answers

According to the figure, what role does a peptide play in TLR activation?

The peptide links the sugar and acyl group, and stabilizes the binding of the TLR. Signup and view all the answers

What type of cells are crucial for bridging the innate and adaptive immune responses, based on the diagram?

Dendritic cells. Signup and view all the answers

According to the diagram, what is one type of molecule that TLR activation might detect?

Viral RNA or DNA. Signup and view all the answers

What is the relevance of ‘unmethylated’ in the context of TLR9 activation?

Unmethylated DNA is associated with microbial DNA and not typically found in the host, allowing it to be recognized by the immune system. Signup and view all the answers

What is the immediate result of activation of signalling transduction pathways by TLRs?

Activation of genes. Signup and view all the answers

What is the role of cytokines released during immune activation?

To work together and regulate the immune response. Signup and view all the answers

Which branch of the immune system, innate or adaptive, can distinguish the type of infection?

Innate immunity Signup and view all the answers

What kind of immune response do TLRs help initiate when they detect a pathogen?

Antiviral immune response. Signup and view all the answers

What type of immune cell releases cytokines that work together?

Monocytes. Signup and view all the answers

What type of molecule are cytokines?

Helical Proteins Signup and view all the answers

Which interleukins are listed as key anti-inflammatory cytokines?

IL-1RA, 10, 27, 35, 37 Signup and view all the answers

What process do pro-inflammatory cytokines induce in leukocytes?

activation Signup and view all the answers

Where are regulatory T cells located?

In follicles (lymphoid) Signup and view all the answers

What is the general function of the highlighted Interleukins?

Anti-inflammatory actions Signup and view all the answers

What is another term for 'vasodilation', as listed in the diagram?

anneut Signup and view all the answers

Which molecules are important in T cell differentiation?

Cytokines and antigen Signup and view all the answers

Is IL-1RA a pro-inflammatory or anti-inflammatory cytokine?

anti-inflammatory Signup and view all the answers

Study Notes

Innate Immunity

Immunity distinguishes self from non-self (microorganisms, tumors, etc.)
Innate immunity uses germline-encoded receptors to detect non-self
Innate immunity does not have somatic recombination

Pattern Recognition Receptors (PRRs)

PRRs detect pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs)
Toll-like receptors (TLRs) are a type of PRR
TLRs are type I transmembrane proteins with two domains:
- Leucine-rich repeats (LRRs): horseshoe-shaped, extracellular/endosomal sensor of PAMPs/DAMPs
- Toll/interleukin-1 receptor (TIR) domain: globular, cytosolic, signal transduction
Thirteen TLRs are found in mammals (10 in humans, 13 in mice)
TLRs have various subcellular localizations and bind to different ligands

TLR Subtypes

TLR1/2: bind Gram-positive bacteria triacylated lipopeptides
TLR3: binds doublestranded RNA (dsRNA)
TLR4: binds lipopolysaccharide (LPS) from Gram-negative bacteria (specifically Lipid A); requires MD-2 co-receptor
TLR5: binds bacterial flagellin
TLR6/2: bind diacylated lipopeptides from Gram-positive bacteria
TLR7/8: bind single-stranded RNA (ssRNA)
TLR9: binds unmethylated CpG DNA
TLR10: similar structure to TLR1/6, functions likely anti-inflammatory

Cytokines

Small proteins (5–30 kDa)
Released by many cell types, play a crucial role in cell-cell interactions
Function via autocrine and paracrine mechanisms
Approximately 250 cytokines in humans
Classes based on structure and function: interleukins, interferons, tumor necrosis factor (TNF) family, colony stimulating factors, chemokines, growth factors, and others

Role of TLRs in Adaptive Immunity

TLRs stimulate antigen processing in antigen-presenting cells (APCs) by phagocytosis
They induce the expression of co-stimulatory molecules on APCs and release cytokines
TLRs help the adaptive immune system by relaying information about infections

Cytokine Signaling

Cytokines initiate signal transduction pathways, turning on gene expression in target cells.
Pro-inflammatory cytokines (TNF-α, IL-1β, IL-12) induce inflammation, fever, and attract immune cells to sites of infection or damage
Anti-inflammatory cytokines (IL-1ra, IL-10, TGF-β) dampen excessive inflammation

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Description

Test your knowledge on cytokines and Toll-like receptors (TLRs) with this quiz. Explore the functions of cytokines, the role of caspases, and the recognition mechanisms of various TLRs. Challenge yourself with questions about their structural features and interactions in the immune response.