immunology

    Cards (187)

    • What are the challenges faced by the immune system due to microbes?

      Microbes are ubiquitous, diverse, rapidly evolving, and can hijack cellular machinery.
    • What types of intracellular pathogens are mentioned in the study material?

      Viruses, intracellular bacteria, and intracellular parasites.
    • What are the physical and chemical defenses of the immune system?

      • Skin barrier function
      • β-defensins and cathelicidins produced by keratinocytes
      • Chemical substances like lysozyme and stomach acid
      • Antimicrobial peptides secreted by epithelial cells and phagocytes
    • What is the role of β-defensins and cathelicidins in the immune system?

      They are antimicrobial agents produced by keratinocytes.
    • How do antimicrobial peptides function in the immune response?

      They disrupt the cell membranes of bacteria, fungi, and some viral envelopes.
    • What are the two main types of immune responses?
      1. Innate immune response
      • Immediate response
      • Recognizes common pathogen structures
      1. Adaptive immune response
      • Stimulated by specific pathogens
      • Reacts to a wide variety of antigens
    • What is the definition of innate immunity?
      Innate immunity is the immediate response from mechanisms in place before an infection occurs.
    • What is the role of macrophages in the immune system?

      Macrophages patrol tissues and are involved in phagocytosis.
    • What is phagocytosis?

      Phagocytosis is the internalization of particulate matter by engulfment.
    • What is opsonization?

      Opsonization is the coating of microbes with proteins to facilitate phagocytosis.
    • What are the types of phagocytes mentioned in the study material?

      • Macrophages
      • Granulocytes (neutrophils, eosinophils, basophils)
      • Immature dendritic cells
    • What is the primary function of neutrophils?

      To engulf and destroy pathogens.
    • What is the role of eosinophils in the immune system?

      Eosinophils attack the cell walls of parasites and can damage host tissue.
    • What do basophils contain that aids in defense against parasites?

      Potent inflammatory mediators.
    • Where are mast cells found and what is their function?
      Mast cells are found in tissues and aid in defense against parasites and allergic responses.
    • What is the role of natural killer (NK) cells in the immune system?

      NK cells can kill virally infected or malignant host cells and produce cytokines.
    • How can NK cells be activated?

      By engaging activating receptors or by the loss of MHC class I molecules from unhealthy cells.
    • What is the process called when NK cells kill antibody-coated cells?

      Antibody-dependent cell cytotoxicity (ADCC).
    • What happens to MHC class I molecules during viral infection and cancer?

      MHC class I can be downregulated, leading to NK cell activation.
    • What are the key components of the immune system?

      • Tissues
      • Organs
      • Cells
      • Molecules
      • Genes
    • What are the steps involved in phagocytosis?

      1. Recognition of the pathogen
      2. Engulfment of the pathogen
      3. Formation of a phagosome
      4. Destruction of the pathogen
    • What are the two types of immune systems mentioned in the study material?
      Innate and adaptive immune systems
    • What are the key differences between innate and adaptive receptors?
      • Innate receptors: Limited number encoded in genome, clonally distributed, recognizes broad groups of pathogens, triggers immediate response.
      • Adaptive receptors: Huge number generated by gene rearrangement, recognizes very specific pathogens, triggers slower response (days to weeks).
    • What do Pattern Recognition Receptors (PRRs) recognize?

      Pathogen Associated Molecular Patterns (PAMPs)
    • Where can PRRs be located?

      On cell surface, endosomal membranes, and in the cytosol
    • What are Toll-Like Receptors (TLRs)?

      They are a type of PRR that recognizes PAMPs
    • What are the consequences of detecting PAMPs by PRRs?

      • Aids phagocytosis
      • Activates innate cells
      • Promotes inflammatory mediators.
      • direct attack of micro-organism by soluble PRR molecules which enhances phagocytosis and PRR bound PAMPS
    • What are Danger Associated Molecular Patterns (DAMPs)?
      Host proteins released during cell injury that activate the immune system
    • What is the role of complement in the immune system?

      • Promotes phagocytosis through opsonization
      • Induces inflammatory responses
      • Directly kills pathogens
    • What triggers the classical pathway of complement activation?

      The presence of an antibody-antigen complex
    • What triggers the alternative pathway of complement activation?

      Microbial surface structures, e.g., LPS
    • What triggers the lectin pathway of complement activation?

      Mannose residues on pathogen glycoproteins binding to host lectins
    • What is the function of C3 convertase in the complement system?

      It converts C3 into C3a and C3b
    • What are C3a and C5a in the context of inflammation?

      Powerful anaphylatoxins that cause mast cell degranulation and promote vasodilation
    • What role does C5a play in the immune response?

      It is a chemotactic factor that directs the movement of leukocytes
    • How does C3b contribute to phagocytosis?

      It attaches to the microbe and is recognized by complement receptor 1 (CR1) on phagocytes
    • What triggers the formation of the membrane attack complex (MAC)?

      C5b triggers the formation of MAC
    • What are cytokines?

      Soluble proteins produced by various cell types critical for immune responses
    • What are the different actions of cytokines?

      • Autocrine, paracrine, or endocrine actions
      • Proinflammatory (e.g., IL-1, IL-6)
      • Anti-inflammatory (e.g., TGF-β, IL-10)
      • Involved in cell growth and differentiation
      • Involved in chemotaxis (e.g., CCL3, CXCL1)
    • What are the characteristics of cytokines?
      • Pleiotropic: More than one effect
      • Redundancy: Several cytokines can have the same effect
      • Synergy: Combined effect greater than individual effects
      • Antagonism: One cytokine inhibits another
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