Podcast
Questions and Answers
Which cells express the pattern recognition receptors used by the innate immune system?
Which cells express the pattern recognition receptors used by the innate immune system?
Where are Toll-like receptors (TLRs) located in the cell?
Where are Toll-like receptors (TLRs) located in the cell?
How many different functional receptors are formed by the 10 different Toll-like receptor (TLR) proteins in humans?
How many different functional receptors are formed by the 10 different Toll-like receptor (TLR) proteins in humans?
What is the role of Toll-like receptors (TLRs) in protecting flies against fungal infections?
What is the role of Toll-like receptors (TLRs) in protecting flies against fungal infections?
Signup and view all the answers
Which cellular compartments do the pattern recognition receptors used by the innate immune system to detect microbes and damaged cells locate in?
Which cellular compartments do the pattern recognition receptors used by the innate immune system to detect microbes and damaged cells locate in?
Signup and view all the answers
Which protein family do the receptors for PAMPs and DAMPs belong to?
Which protein family do the receptors for PAMPs and DAMPs belong to?
Signup and view all the answers
What is the number of different functional receptors formed by the 10 different Toll-like receptor (TLR) proteins in humans?
What is the number of different functional receptors formed by the 10 different Toll-like receptor (TLR) proteins in humans?
Signup and view all the answers
What is the role of Toll-like receptors (TLRs) in protecting flies against fungal infections?
What is the role of Toll-like receptors (TLRs) in protecting flies against fungal infections?
Signup and view all the answers
Which type of microbial products are recognized by Toll-like receptors (TLRs)?
Which type of microbial products are recognized by Toll-like receptors (TLRs)?
Signup and view all the answers
Where are TLRs specific for microbial proteins, lipids, and polysaccharides located?
Where are TLRs specific for microbial proteins, lipids, and polysaccharides located?
Signup and view all the answers
Which major family of cellular receptors is NOT involved in innate immunity?
Which major family of cellular receptors is NOT involved in innate immunity?
Signup and view all the answers
What do TLR signals activate within the cell?
What do TLR signals activate within the cell?
Signup and view all the answers
What do mutations affecting TLRs or their signaling molecules indicate?
What do mutations affecting TLRs or their signaling molecules indicate?
Signup and view all the answers
What type of products do plasma membrane TLRs recognize?
What type of products do plasma membrane TLRs recognize?
Signup and view all the answers
Study Notes
Innate Immune System Receptors and Functions
- Toll-like receptors (TLRs) recognize various microbial products such as lipopeptides, peptidoglycans, bacterial LPS, flagellin, dsRNA, ssRNA, and unmethylated CpG DNA.
- TLRs specific for microbial proteins, lipids, and polysaccharides are located on cell surfaces, while those recognizing nucleic acids are in endosomes.
- There are five major families of cellular receptors in innate immunity: TLRs, C-type lectin receptors (CLRs), NOD-like receptors (NLRs), RIG-like receptors (RLRs), and cytosolic DNA sensors (CDSs).
- TLR signals activate transcription factors, such as NF-κB and interferon regulatory factors (IRFs), stimulating the expression of cytokines and proteins involved in inflammation and antiviral response.
- Mutations affecting TLRs or their signaling molecules can cause rare autosomal recessive diseases characterized by recurrent infections, indicating the importance of these pathways in host defense against microbes.
- Different TLRs recognize structurally diverse products of microbes, with plasma membrane TLRs specific for bacterial cell wall components and endosomal TLRs recognizing nucleic acids.
- TLR-4 is specific for bacterial LPS and binds to MD2, while TLR-5 is specific for bacterial flagellin.
- TLRs contain a ligand-binding domain composed of leucine-rich motifs and a cytoplasmic signaling Toll-like interleukin-1 (IL-1) receptor (TIR) domain, activating signaling mechanisms that involve adaptor proteins and lead to the activation of transcription factors.
- TLR engagement by bacterial or viral molecules leads to the activation of NF-κB, which promotes the expression of cytokines, adhesion molecules, and costimulators, resulting in acute inflammation and stimulation of adaptive immunity.
- TLRs in endosomes activate transcription factors and lead to the production of interferon regulatory factors (IRFs), which stimulate the production of type 1 interferon (IFN alpha, beta) and antiviral state.
- TLR-3 mutations make individuals susceptible to herpes simplex virus infections, particularly encephalitis, while mutations in MyD88, a signal transduction adaptor protein downstream of several TLRs, make individuals susceptible to bacterial pneumonias.
- TLRs play a crucial role in host defense against microbes by recognizing a wide range of microbial products and activating signaling mechanisms that lead to inflammation, antiviral defense, and the production of antiviral cytokines.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge about the pattern recognition receptors used by the innate immune system to detect microbes and damaged cells. Explore the expression and location of these receptors on different cell types and cellular compartments.
