Immunology Overview Quiz
44 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of the immune system according to the provided text?

  • To indiscriminately attack all foreign substances.
  • To initiate somatic recombination of gene products.
  • To solely target and eliminate aged cells.
  • To distinguish between 'self' and 'non-self'. (correct)
  • Which of the following is NOT identified as a 'non-self' entity by the innate immune system according to the text?

  • Grafted tissues.
  • Healthy cells. (correct)
  • Microorganisms.
  • Necrotic cells.
  • What is the role of Pattern Recognition Receptors (PRRs) in the innate immune response?

  • To initiate somatic recombination in response to pathogens.
  • To identify and respond to 'self' molecular patterns.
  • To identify and respond to non-self molecular patterns such as PAMPs and DAMPs. (correct)
  • To prevent any activation of the immune system.
  • What is a key difference between innate immunity and adaptive immunity?

    <p>Innate immunity uses germ cell-encoded gene products, while adaptive immunity is not mentioned. (C)</p> Signup and view all the answers

    What does the text indicate PAMPs and DAMPs represent?

    <p>Molecular patterns associated with pathogens and danger, respectively. (C)</p> Signup and view all the answers

    Which of the following cytokines is NOT a member of the class-I helical cytokines?

    <p>IL-10 (C)</p> Signup and view all the answers

    Which of these is a characteristic of the IL-18 family of cytokines?

    <p>They interact with Smad3 to promote anti-inflammatory responses. (B)</p> Signup and view all the answers

    What is the key structural difference between Class-I and Class-II helical cytokines?

    <p>Class-II cytokines have a higher number of packed helices. (C)</p> Signup and view all the answers

    Which of the following cytokines is primarily involved in tissue repair?

    <p>IL-22 (A)</p> Signup and view all the answers

    Which of the following cytokines is NOT directly involved in activating T cells?

    <p>IL-3 (B)</p> Signup and view all the answers

    Which of these cytokine families has members that are primarily involved in skin inflammation?

    <p>IL-36 family (A)</p> Signup and view all the answers

    What is the core function of Class-I helical cytokines?

    <p>Immune cell differentiation and activation (B)</p> Signup and view all the answers

    What distinguishes the two major families of helical cytokines: Class-I and Class-II?

    <p>Their structural organization (B)</p> Signup and view all the answers

    Which Toll-like receptor (TLR) is known to form homodimers?

    <p>TLR4 (B)</p> Signup and view all the answers

    Which TLR recognizes intracellular components of microorganisms within endosomal membranes?

    <p>TLR8 (D)</p> Signup and view all the answers

    Which bacterial component is directly recognized by TLR4?

    <p>Lipid A of LPS (A)</p> Signup and view all the answers

    The MD2 protein associated with TLR4 binds to how many acyl groups?

    <p>Five (C)</p> Signup and view all the answers

    What structural feature of LPS facilitates TLR4 dimerization?

    <p>Lipid A (A)</p> Signup and view all the answers

    Which of these TLRs are located in the plasma membrane?

    <p>TLR2, TLR4 &amp; TLR5 (A)</p> Signup and view all the answers

    Which receptor specifically recognizes 23S bacterial rRNAs?

    <p>TLR13 (mouse) (C)</p> Signup and view all the answers

    What is the role of the hydrophobic groups of MD2?

    <p>To bind to the acyl groups of Lipid A (C)</p> Signup and view all the answers

    Based on the information, which are examples of extracellular TLRs?

    <p>TLR2 and TLR4 (D)</p> Signup and view all the answers

    What is the result of TLR4 activation?

    <p>Stabilization of TLR4 dimerization (B)</p> Signup and view all the answers

    Which of the following is a key pro-inflammatory cytokine indicated in the content?

    <p>IL-8 (A)</p> Signup and view all the answers

    What is a primary function of anti-inflammatory cytokines mentioned in the content?

    <p>Inducing regulatory immune cell development (B)</p> Signup and view all the answers

    Which cytokines are known to inhibit pro-inflammatory immune cell proliferation?

    <p>IL-10 and TGF-β (A)</p> Signup and view all the answers

    What consequence is associated with the over-expression of pro-inflammatory cytokines?

    <p>Tissue damage (C)</p> Signup and view all the answers

    How do anti-inflammatory cytokines interfere with pro-inflammatory responses?

    <p>By blocking receptor activation (D)</p> Signup and view all the answers

    Which type of cells primarily become activated through TLR signaling cascades?

    <p>Innate immune cells (C)</p> Signup and view all the answers

    Which DNA sequence is important for the dimerization of the prometer in TLR activation?

    <p>5’-XCX---CpG-3’ (D)</p> Signup and view all the answers

    What is a consequence of TLR activation in innate immune cells?

    <p>Activation of hundreds of genes (B)</p> Signup and view all the answers

    Which of the following is NOT expressed by TLR4 upon activation?

    <p>T cell receptors (A)</p> Signup and view all the answers

    What process occurs to TLR9 and DNAs before their full activation?

    <p>Cleavage (A)</p> Signup and view all the answers

    What kind of immune cells are NOT activated by TLRs?

    <p>T cells (D)</p> Signup and view all the answers

    What triggers the cooperative activation of the prometer in TLR signaling?

    <p>Binding of DNA sequences (D)</p> Signup and view all the answers

    Which cytokines are typically associated with TLR activation?

    <p>Mitogenic cytokines and chemokines (D)</p> Signup and view all the answers

    What role does F126 of MD2 play in relation to TLR4?

    <p>It allows MD2 to stabilize TLR4-TLR4 dimerization. (A)</p> Signup and view all the answers

    Which components are involved in stabilizing the TLR4-TLR4 interaction?

    <p>Phosphate groups and acyl groups from LPS. (C)</p> Signup and view all the answers

    What does TLR2 primarily sense?

    <p>Lipoproteins and lipoteichoic acids. (D)</p> Signup and view all the answers

    Which of the following correctly describes the structure of TLR2?

    <p>TLR2 can heterodimerize with TLR1 and TLR6. (A)</p> Signup and view all the answers

    What type of acyl groups does TLR1 bind to, and in which context?

    <p>Amide-linked acyl groups as found in OspA and Pam3GSK4. (C)</p> Signup and view all the answers

    Which statement is true regarding TLR6?

    <p>TLR6 involves interaction with peptides and teichoic acids. (D)</p> Signup and view all the answers

    How many acyl groups are involved in the binding of TLR2?

    <p>Two ester-linked acyl groups. (A)</p> Signup and view all the answers

    What type of bacteria is associated with TLR6's role?

    <p>Both Gram-positive and Gram-negative bacteria. (C)</p> Signup and view all the answers

    Flashcards

    Self vs. Non-self

    The ability of the immune system to distinguish between the body's own cells and foreign invaders.

    Innate Immunity

    The first line of defense against infection, it is immediate and non-specific.

    PAMPs/MAMs & DAMPs

    Molecular patterns present on microbes or damaged cells that are recognized by the immune system.

    Pattern Recognition Receptors (PRRs)

    Receptors on immune cells that recognize PAMPs/MAMs & DAMPs to trigger an immune response.

    Signup and view all the flashcards

    Toll-Like Receptors (TLRs)

    A type of PRR that recognizes specific microbial patterns and triggers an immune response.

    Signup and view all the flashcards

    Pathogen-associated molecular pattern (PAMP)

    A molecule that acts as a signal of infection, recognized by TLRs.

    Signup and view all the flashcards

    TLR4

    A type of TLR that recognizes lipid A, a component of lipopolysaccharide (LPS) found in the outer membrane of Gram-negative bacteria.

    Signup and view all the flashcards

    Lipopolysaccharide (LPS)

    A component of bacterial cell walls, primarily found in Gram-negative bacteria.

    Signup and view all the flashcards

    Lipid A

    The part of LPS that is recognized by TLR4.

    Signup and view all the flashcards

    MD2 (TLR4-associated protein)

    A protein that associates with TLR4 and is essential for its activation by LPS.

    Signup and view all the flashcards

    TLR4 dimerization

    A process by which TLR4, in association with MD2, forms a dimer (two molecules joined together).

    Signup and view all the flashcards

    TLR4 activation

    The activation of TLR4 by LPS leads to the production of signaling molecules that trigger an immune response.

    Signup and view all the flashcards

    Penta-acylated lipid A

    A lipid A molecule with five acyl chains.

    Signup and view all the flashcards

    TLR4 activation by penta-acylated lipid A

    An interaction between TLR4 and LPS that leads to a stronger immune response compared to the interaction with tetra-acylated lipid A.

    Signup and view all the flashcards

    IL-1 Family Cytokines

    A family of cytokines that includes IL-1α, IL-1β, IL-33, and IL-18. They are known for triggering inflammation and activating T cells.

    Signup and view all the flashcards

    How does TLR4 recognize LPS?

    TLR4 recognizes a specific structure of LPS (lipopolysaccharide) found on Gram-negative bacteria. It binds to the hydrophobic region of the LPS molecule, where lipid A is present.

    Signup and view all the flashcards

    Toll-like Receptor (TLR) Binding Domain

    A protein domain found in IL-1 family cytokines that is responsible for binding to and activating the Toll-like receptor (TLR) pathway.

    Signup and view all the flashcards

    What makes LPS special for TLR4 recognition?

    LPS has a unique structure composed of a lipid (lipid A) and sugar chains. The lipid A portion is crucial for TLR4 binding.

    Signup and view all the flashcards

    What happens when TLR4 binds to LPS?

    TLR4 on immune cells dimerizes (forms a pair) when it binds to LPS. This dimerization triggers signaling pathways that activate an immune response.

    Signup and view all the flashcards

    IL-1α

    A small, soluble protein that can activate T cells and trigger inflammation.

    Signup and view all the flashcards

    Which part of LPS binds TLR4?

    The sixth acyl group on LPS binds directly to a specific pocket on TLR4, further stabilizing the TLR4 dimer. This interaction plays a critical role in activating the immune response.

    Signup and view all the flashcards

    IL-1β

    A protein that is produced by the immune system and is involved in the inflammatory response. It plays a crucial role in activating T cells.

    Signup and view all the flashcards

    What does TLR2 recognize?

    TLR2 is a pattern recognition receptor that recognizes different microbial patterns, including lipoteichoic acids (LTA) and lipoproteins from various bacteria.

    Signup and view all the flashcards

    IL-33

    A cytokine involved in the inflammatory response, particularly in the skin.

    Signup and view all the flashcards

    How does TLR2 interact with other TLRs?

    TLR2 can exist as a heterodimer, meaning it pairs with another TLR. For example, TLR2 can form a dimer with TLR1 or TLR6, allowing it to recognize different bacterial patterns.

    Signup and view all the flashcards

    IL-18

    An important cytokine that signals the body to fight infection and activate T cells. It is often released during inflammation.

    Signup and view all the flashcards

    What are the co-receptors for TLR2?

    TLR2 requires different co-receptors to recognize specific bacterial structures. TLR1 binds to two amid-linked acyl groups, while TLR6 binds to teichoic acid and a peptide. This allows TLR2 to recognize a wider range of bacterial signals.

    Signup and view all the flashcards

    Class-I Helical Cytokines

    A family of cytokines that includes IL-2, IL-4, IL-6, and IL-12. These cytokines are involved in immune cell differentiation and activation.

    Signup and view all the flashcards

    Cytokines

    A group of signaling molecules that help cells communicate and coordinate immune responses. They can be pro-inflammatory, like IL-8, or anti-inflammatory, like IL-10.

    Signup and view all the flashcards

    How does TLR2 recognize different bacteria?

    TLR2 binds to various bacteria by recognizing different molecular patterns on their surface, including lipoteichoic acids and lipoproteins. These patterns are unique to specific bacterial groups.

    Signup and view all the flashcards

    Class-II Helical Cytokines

    A group of cytokines, including IL-10, IL-22, and IL-28/29. They have a wide range of functions, including immune modulation, tissue repair, and antiviral activity.

    Signup and view all the flashcards

    Pro-inflammatory Cytokines

    Cytokines that promote inflammation and immune activation. They can enhance blood vessel dilation and attract immune cells to the site of infection or injury.

    Signup and view all the flashcards

    Anti-inflammatory Cytokines

    Cytokines that help suppress inflammation and regulate the immune system. They can inhibit the activation of pro-inflammatory pathways and promote the development of regulatory immune cells.

    Signup and view all the flashcards

    IL-8 (Interleukin-8)

    A cytokine involved in attracting immune cells to the site of inflammation. It plays a crucial role in inflammatory responses by enhancing blood vessel dilation and leukocyte movement.

    Signup and view all the flashcards

    IL-10 (Interleukin-10)

    A cytokine that helps regulate the immune system by inhibiting the proliferation of pro-inflammatory immune cells. It contributes to the development of regulatory T cells, aiding in immune tolerance.

    Signup and view all the flashcards

    Pathogen-Associated Molecular Patterns (PAMPs) or Microbe-Associated Molecular Patterns (MAMs)

    A molecule present on microbes or damaged cells that is recognized by the immune system.

    Signup and view all the flashcards

    CpG DNA

    A type of PAMP found in bacterial DNA and recognized by TLR9.

    Signup and view all the flashcards

    Immune signaling molecules

    The release of various immune signaling molecules, such as cytokines and chemokines, in response to TLR9 activation.

    Signup and view all the flashcards

    Immune cell activation

    A type of immune cell that responds to TLR signaling and triggers an immune response.

    Signup and view all the flashcards

    Immune response genes

    A group of genes activated by TLR signaling that help fight off infection.

    Signup and view all the flashcards

    Study Notes

    Immunology 3300B (2025)

    • Course covers Pattern Recognition Receptors (PRRs) and Cytokines.
    • Instructor: Dr. Sung KIM
    • Contact Information: Siebens-Drake Research Institute, Rm. 119; Phone: 850-2961; Email: [email protected]

    Objective

    • Introduce innate immune activation mechanisms through PRRs and immune system communication via cytokines.

    Topics

    • PRRs: Toll-Like Receptors (TLRs)
    • Primer on Cytokines

    Course Materials

    • Lecture and lecture slides

    Immunity

    • Fundamental to discriminating "self" from "non-self".
    • "Non-self" includes microorganisms, tumors, transplanted tissues, necrotic cells, aged cells, environmental substances.
    • Innate immunity rapidly identifies "non-self" through germline-encoded genes, without somatic recombination.
    • Microbial classes carry molecular patterns (either surface-anchored or secreted).
    • Multicellular organisms have pattern recognition receptors that signal (only in vertebrates) to the adaptive immune system.
    • Molecular patterns: include pathogen-associated molecular patterns (PAMPs/MAMs) and danger-associated molecular patterns (DAMPs).

    Key PRRs and Their Ligands

    • This table lists various types and subtypes of PRRs and their known microbial/endogenous ligands:
    • Includes Toll-Like Receptors (TLRs), C-type lectin receptors, Nod-like receptors, and RIG-I-like receptors (RLRs). (Detailed table of PRRs and ligands is not summarized due to the large size and it being tabular data.)

    Toll-Like Receptors (TLRs)

    • Type I transmembrane proteins with conserved domains.
    • Leucine-Rich Repeats (LRRs): Horseshoe shape, acts as PAMP/DAMP sensors.
    • Toll/IL-1 Receptor (TIR): Globular shape in cytoplasm, signal transduction site.
    • Total 13 TLRs identified in mammals (with 10 in humans & 13 in mice).
    • TLR structure:
      • extracellular domain (ECD)
      • transmembrane domain (TM)
      • cytoplasmic domain (CD)
    • Subcellular locations and ligands vary among TLRs. (Specific details from images are not included).

    Endosomal Sensors of Microbial RNAs

    • TLR3 detects double-stranded RNA (dsRNA).
    • TLR7 & TLR8 detect single-stranded RNA (ssRNA).
    • TLR9 detects unmethylated CpG DNA.
    • All the above TLRs function in endosomes/phagosomes.

    Cytokine Signaling Cascades

    • TLR activation triggers signaling cascades.
    • Cascades activate gene expression of cytokines & chemokines for immune response. (Diagrammatic details omitted due to complexity)

    Role of TLRs in Adaptive Immunity

    • TLRs initiate antigen processing in antigen presenting cells (APCs).
    • Enhance co-stimulatory molecule expression.
    • Release cytokines to guide adaptive immune responses.
    • TLRs relay infection source for adaptive immune system.

    A Primer on Cytokines

    • Small proteins (5-30kDa)
    • Released by many cell types.
    • Essential for cell-cell interactions & immune function (works at very low concentrations).
    • Pleiotropic, redundant, and interactive (synergistic or antagonistic).
    • Approximately 250 cytokines in humans.

    Six Cytokine Groups

    • Interleukins (between leukocytes).
    • Interferons (viral infection).
    • TNF family (tumor necrosis & inducing).
    • Colony Stimulating Factors (CSF).
    • Chemokines.
    • Unassigned. (Detailed information omitted).

    IL Subgroups

    • Based on molecular structure (detailed groupings are not summarized).

    IL-1 Family

    • Involved in inflammatory responses.
    • Bio-activated via proteases.
    • Sub-divided based on position of AXD motifs. (further details omitted).

    Class-I & Class-II Helical Cytokines

    • Involved in immune cell differentiation & activation.
    • Class I: folded into bundle of four alpha helices.
    • Class II: folded into bundle of six or seven helices. (detailed info omitted).

    Key Cytokines Influencing T cell Differentiation

    • Cytokines play critical roles in guiding T cell differentiation. (Diagram omitted due to complexity).

    Key Pro-inflammatory Cytokines

    • Inflammatory factors induced by leukocytes in response to tissue injury/microbial infection.
    • Affects local and systemic processes (detailed info omitted in summary).

    Key Anti-inflammatory Cytokines

    • Interfere with pro-inflammatory responses at the receptor, signaling, or transcription factor level.
    • Inhibit pro-inflammatory immune cells (e.g., IL-10, IL-27).
    • Development of regulatory immune cells (e.g. IL-2, IL-4, IL-35). (Detailed mechanisms omitted)

    Questions

    • Why do both recombinant IL-2 and IL-2 inhibitors cause inflammation? (Detailed answer omitted)

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Description

    Test your knowledge on the immune system's functions and components. This quiz covers concepts related to innate and adaptive immunity, cytokines, and their roles in immune responses. Explore how the immune system identifies non-self entities and the significance of various immune receptors.

    More Like This

    Cytokines and Innate Immunity Quiz
    7 questions
    Innate Immune Response Quiz
    10 questions
    Use Quizgecko on...
    Browser
    Browser