Podcast
Questions and Answers
What role does innate immunity play in the immune response?
What role does innate immunity play in the immune response?
- It is effective only after an infection has occurred.
- It memorizes specific pathogens for future attacks.
- It provides a quick, non-specific blockade of infection. (correct)
- It primarily relies on antibodies to neutralize threats.
Which of the following is NOT a method of prevention employed by the immune system?
Which of the following is NOT a method of prevention employed by the immune system?
- Mucosal defenses in various tracts.
- Secretion of antibodies by plasma cells. (correct)
- Keratinized skin providing a physical barrier.
- Cilia helping to move bacteria out of the body.
How do commensal microbes contribute to the immune system?
How do commensal microbes contribute to the immune system?
- By replacing damaged immune cells after an infection.
- By increasing the number of pathogens present in the body.
- By enhancing immune responses and preventing pathogen colonization. (correct)
- By exclusively producing vitamins necessary for metabolism.
What is the primary function of lysozymes secreted by sebaceous glands?
What is the primary function of lysozymes secreted by sebaceous glands?
What can be a consequence of over-washing hands?
What can be a consequence of over-washing hands?
Which component of the immune system is primarily involved in mechanically clearing bacterial pathogens?
Which component of the immune system is primarily involved in mechanically clearing bacterial pathogens?
What is an example of the role played by lactoferrin in the immune system?
What is an example of the role played by lactoferrin in the immune system?
What characteristic is true about the innate immune response?
What characteristic is true about the innate immune response?
What is a primary function of macrophages in innate immunity?
What is a primary function of macrophages in innate immunity?
Which substance is produced by macrophages to help kill bacteria?
Which substance is produced by macrophages to help kill bacteria?
What initiates the activation of Natural Killer (NK) cells?
What initiates the activation of Natural Killer (NK) cells?
How do infected cells influence NK cell activation?
How do infected cells influence NK cell activation?
What is the role of the Complement System in innate immunity?
What is the role of the Complement System in innate immunity?
Which pathway in the Complement System involves antibody-antigen complexes?
Which pathway in the Complement System involves antibody-antigen complexes?
What is the function of C3b in the Complement System?
What is the function of C3b in the Complement System?
What effect does the Membrane Attack Complex (MAC) have on target cells?
What effect does the Membrane Attack Complex (MAC) have on target cells?
What is the primary role of reactive oxygen species (ROS) produced by macrophages?
What is the primary role of reactive oxygen species (ROS) produced by macrophages?
What do Killing Inhibiting Receptors (KIRs) on NK cells do?
What do Killing Inhibiting Receptors (KIRs) on NK cells do?
What is the primary role of dietary fiber in relation to gut health?
What is the primary role of dietary fiber in relation to gut health?
Which component of the immune system is responsible for targeting microbes once inside the body?
Which component of the immune system is responsible for targeting microbes once inside the body?
What characterizes adaptive immunity?
What characterizes adaptive immunity?
Which phase of infection is characterized by no visible signs of disease despite bacterial colonization?
Which phase of infection is characterized by no visible signs of disease despite bacterial colonization?
What function do antibodies serve in the immune response?
What function do antibodies serve in the immune response?
Which of the following is NOT a function of neutrophils in the immune response?
Which of the following is NOT a function of neutrophils in the immune response?
What triggers the release of cytokines in response to pathogen recognition?
What triggers the release of cytokines in response to pathogen recognition?
Which white blood cells are derived from monocytes?
Which white blood cells are derived from monocytes?
What role do dendritic cells play in the immune system?
What role do dendritic cells play in the immune system?
Which of the following is considered a pro-inflammatory function of macrophages?
Which of the following is considered a pro-inflammatory function of macrophages?
What is the role of serum transferrin in the immune response?
What is the role of serum transferrin in the immune response?
What is the half-life of neutrophils in vivo?
What is the half-life of neutrophils in vivo?
What distinguishes Toll-like receptors (TLRs) from other pattern recognition receptors?
What distinguishes Toll-like receptors (TLRs) from other pattern recognition receptors?
What is one function of neutrophil extracellular traps (NETs)?
What is one function of neutrophil extracellular traps (NETs)?
What defines the term 'immune' in the context of the immune system?
What defines the term 'immune' in the context of the immune system?
What is the primary function of keratinized skin in the immune system?
What is the primary function of keratinized skin in the immune system?
Which method is employed by the innate immune system to remove infectious agents?
Which method is employed by the innate immune system to remove infectious agents?
How do commensal bacteria support the immune system?
How do commensal bacteria support the immune system?
What is the role of mucosal defenses in the respiratory tract?
What is the role of mucosal defenses in the respiratory tract?
How do lysozymes contribute to immune defense?
How do lysozymes contribute to immune defense?
What is a function of lactoferrin in the immune system?
What is a function of lactoferrin in the immune system?
What happens during over-washing of hands in relation to immune defense?
What happens during over-washing of hands in relation to immune defense?
What is the primary purpose of reactive nitrogen species (RNS) produced by macrophages?
What is the primary purpose of reactive nitrogen species (RNS) produced by macrophages?
How do Natural Killer (NK) cells discriminate between healthy and infected cells?
How do Natural Killer (NK) cells discriminate between healthy and infected cells?
What is the consequence of downregulating MHC class I on infected cells for NK cell activity?
What is the consequence of downregulating MHC class I on infected cells for NK cell activity?
Which pathway of the Complement System is initiated by the direct binding of complement proteins to pathogen surfaces?
Which pathway of the Complement System is initiated by the direct binding of complement proteins to pathogen surfaces?
What is the role of perforin in the function of NK cells?
What is the role of perforin in the function of NK cells?
C3a, a product of C3 activation in the Complement System, primarily functions to:
C3a, a product of C3 activation in the Complement System, primarily functions to:
What occurs when the Membrane Attack Complex (MAC) forms in target cells?
What occurs when the Membrane Attack Complex (MAC) forms in target cells?
Which cytokines are significantly released by macrophages to attract neutrophils and monocytes?
Which cytokines are significantly released by macrophages to attract neutrophils and monocytes?
The function of reactive oxygen species (ROS) in macrophages is primarily to:
The function of reactive oxygen species (ROS) in macrophages is primarily to:
What key role does the classical pathway of the Complement System play?
What key role does the classical pathway of the Complement System play?
What is the primary role of adaptive immunity?
What is the primary role of adaptive immunity?
What triggers the activation of T and B cells in the adaptive immune response?
What triggers the activation of T and B cells in the adaptive immune response?
Which immune cells are primarily involved in the phagocytosis of pathogens?
Which immune cells are primarily involved in the phagocytosis of pathogens?
Which of the following statements about neutrophils is true?
Which of the following statements about neutrophils is true?
What is the role of dendritic cells in the immune response?
What is the role of dendritic cells in the immune response?
What defines the asymptomatic phase of infection?
What defines the asymptomatic phase of infection?
Which phase of the immune response is characterized by increased white blood cell production?
Which phase of the immune response is characterized by increased white blood cell production?
Which cellular component is essential for recognizing pathogens and triggering a rapid immune response?
Which cellular component is essential for recognizing pathogens and triggering a rapid immune response?
How do neutrophils contribute to inflammation?
How do neutrophils contribute to inflammation?
What role does serum transferrin play in the immune response?
What role does serum transferrin play in the immune response?
What is one of the main functions of macrophages after a successful immune response?
What is one of the main functions of macrophages after a successful immune response?
Which response is characteristic of the systemic immune response?
Which response is characteristic of the systemic immune response?
What is a key function of antibodies in adaptive immunity?
What is a key function of antibodies in adaptive immunity?
What is the significance of Toll-like receptors (TLRs) in the immune response?
What is the significance of Toll-like receptors (TLRs) in the immune response?
Flashcards
Immune System
Immune System
A complex network of cells, tissues, organs, and substances that fight infections and diseases.
Innate Immunity
Innate Immunity
The body's first line of defense, providing quick, non-specific protection against pathogens.
Pathogen
Pathogen
A disease-causing microbe (bacteria, virus, etc).
Physical Barriers (Innate)
Physical Barriers (Innate)
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Mechanical Defenses (Innate)
Mechanical Defenses (Innate)
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Commensal Microbes
Commensal Microbes
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Lysozymes
Lysozymes
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Immunity
Immunity
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Macrophage Phagocytosis
Macrophage Phagocytosis
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Macrophage Cytotoxicity
Macrophage Cytotoxicity
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Macrophage Cytokine Release
Macrophage Cytokine Release
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NK Cell Activation
NK Cell Activation
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NK Cell Killing Mechanism
NK Cell Killing Mechanism
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Complement System's Role
Complement System's Role
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Complement Activation Pathways
Complement Activation Pathways
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Membrane Attack Complex (MAC)
Membrane Attack Complex (MAC)
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C3b Function
C3b Function
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NK Cell Killing Inhibitory Receptors
NK Cell Killing Inhibitory Receptors
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Commensal bacteria
Commensal bacteria
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Adaptive immunity
Adaptive immunity
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Antibody-mediated response
Antibody-mediated response
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Cell-mediated response
Cell-mediated response
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Dendritic cells
Dendritic cells
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Asymptomatic phase
Asymptomatic phase
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Symptomatic phase
Symptomatic phase
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Acute inflammation
Acute inflammation
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Cytokines
Cytokines
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Neutrophils
Neutrophils
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Phagocytosis
Phagocytosis
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Pattern Recognition Receptors (PRRs)
Pattern Recognition Receptors (PRRs)
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Macrophages
Macrophages
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Natural Killer (NK) cells
Natural Killer (NK) cells
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What does 'being immune' mean?
What does 'being immune' mean?
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How does innate immunity work?
How does innate immunity work?
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What's the role of the skin in innate immunity?
What's the role of the skin in innate immunity?
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What is a commensal microbe?
What is a commensal microbe?
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What are the mechanical defenses of the GI tract?
What are the mechanical defenses of the GI tract?
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How do commensal microbes help the immune system?
How do commensal microbes help the immune system?
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What is the role of lactoferrin?
What is the role of lactoferrin?
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Why is over-washing hands potentially harmful?
Why is over-washing hands potentially harmful?
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Macrophage function
Macrophage function
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How do macrophages kill bacteria?
How do macrophages kill bacteria?
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Lysozyme production in macrophages
Lysozyme production in macrophages
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NK cell function
NK cell function
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KIRs and KARs on NK cells
KIRs and KARs on NK cells
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Complement system's function
Complement system's function
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What are Dendritic cells?
What are Dendritic cells?
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What is the Asymptomatic phase?
What is the Asymptomatic phase?
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What is the Symptomatic phase?
What is the Symptomatic phase?
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What is Acute inflammation?
What is Acute inflammation?
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What are cytokines?
What are cytokines?
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What are Neutrophils?
What are Neutrophils?
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What is Phagocytosis?
What is Phagocytosis?
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What are Pattern Recognition Receptors (PRRs)?
What are Pattern Recognition Receptors (PRRs)?
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What are Macrophages?
What are Macrophages?
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What are Natural Killer (NK) cells?
What are Natural Killer (NK) cells?
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What is the Complement System?
What is the Complement System?
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What are Toll-like receptors (TLRs)?
What are Toll-like receptors (TLRs)?
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Study Notes
Innate Immunity
- Definition: A rapid, non-specific defense mechanism against pathogens. Recognizes pathogens through receptors and sensors, activating cells like macrophages and NK cells, and triggering inflammation to eliminate the threat.
- Prevention Methods:
- Physical barriers: Intact skin (keratinized), sebaceous gland secretions (lysozymes, lipids, ions) create a barrier against microorganisms. Mucosal defenses in the GI, respiratory, and reproductive tracts utilize mechanical cleaning (cilia, flagella), bactericidal factors (lysozymes), and iron limitation.
- Mechanical defenses: Mucus secretion, peristalsis, cilia in the GI, respiratory, urinary, and reproductive tracts remove pathogens.
- Destruction Methods:
- Uses natural killer (NK) cells, neutrophils, macrophages, and the complement system to destroy internal pathogens.
Commensal Microbes
- Role: Outnumber human cells, colonize skin and mucosal surfaces.
- Benefit: Induce protective responses against pathogens, support the immune system, enhance immune responses, and secrete substances to break down invasive bacteria.
- Enhancement: A diverse microbiota (achieved through a balanced diet with fiber) supports immune system function.
Adaptive Immunity
- Definition: A specific and long-term immune response.
- Activation: Infection stimulates T and B cell activation in lymphoid organs. Activated cells migrate to the infection site.
- Antibody-mediated responses:
- Antigen-presenting cells (APCs) present antigens to helper T cells (CD4+).
- Helper T cells coordinate B cell activation.
- B cells produce antibodies that inactivate toxins, enhance phagocytosis, and provide mucosal defense (IgA).
- Cell-mediated responses: Cytotoxic T cells (CTLs) directly kill infected cells
- Link to Innate Immunity: Dendritic cells bridge innate and adaptive immunity by presenting antigens to T cells following an innate response.
Phases of Infection
- Asymptomatic: Pathogens colonize without symptoms.
- Symptomatic: Pathogen evasion triggers symptoms that worsen as immune system weakens, allowing bacterial replication to increase.
Inflammatory Responses
- Local (Acute): Limits injury and infection spread.
- Local Vasculature Response: Vasoconstriction followed by vasodilation.
- Neutrophil infiltration: Kills bacteria.
- Systemic (Acute-Phase):
- Protein production: Marks pathogens for antibody or cell-killing attack.
- Cytokine release: Activates immune cells.
- WBC production: Increased WBC count.
- Fever: Reduces bacterial activity.
- Serum transferrin: Binds iron, limiting bacterial growth.
Cellular Components of Innate Immunity
- Origin: Hemopoietic stem cells in bone marrow differentiate into myeloid and lymphoid progenitors.
- First Line of Defense: Neutrophils, monocytes (macrophages), and NK cells.
Neutrophils
- Role: Phagocytosis and killing of pathogens following skin and mucus barrier traversal.
- Motility: Circulate in blood or infiltrate infection sites.
- Activation: Chemokines produced by inflammatory cells and pathogens.
- Killing Mechanisms: Phagocytosis, toxic granule release (proteases, myeloperoxidase, ROS, lysozymes, cationic proteins), NET formation.
- Short Half-Life: 10-12 hours (in vitro), ~1 day (in vivo).
Monocytes and Macrophages
- Role: Phagocytosis, cytotoxicity, cytokine production.
- Tissue-Specific Types: Microglia (brain), osteoclasts (bone), Kupffer cells (liver), alveolar macrophages (lungs), red pulp macrophages (spleen).
- Pro-inflammatory and Pro-resolution: Involved in fighting infection, removing dead cells, and promoting tissue repair / anti-inflammatory response.
- Killing Mechanisms: Phagocytosis, killing pathogens employing ROS (NADPH, peroxide, OHCL) and RNS (peroxynitrate).
Natural Killer (NK) Cells
- Role: Detect altered self-cells (e.g., virally infected, cancerous).
- Killing Mechanics: Release of perforin and granzymes inducing apoptosis (programming cell death).
- Activation: IL-12 triggers by macrophages.
- "Missing Self": Loss of MHC Class I expression on infected cells triggers NK activation.
Complement System
- Definition: Plasma proteins that work together to enhance immune responses and target pathogens (opsonization, inflammation, pathogen lysis).
- Activation Pathways: Classical (antibody-antigen complexes), MB-lectin, alternative (direct pathogen binding).
- C3 Activation: A key trigger leading to inflammation, opsonization, and target cell lysis.
- Membrane Attack Complex (MAC): Forms pores in target cell membranes, causing cell lysis.
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Description
Explore the essentials of innate immunity, which acts as the body's first line of defense against pathogens through rapid, non-specific mechanisms. Delve into the roles of physical and mechanical barriers, as well as the importance of commensal microbes in maintaining health.
