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Questions and Answers
What role do specific antibodies play in the immune response?
What role do specific antibodies play in the immune response?
Which statement correctly explains the deficiency of the C3/alternative pathway?
Which statement correctly explains the deficiency of the C3/alternative pathway?
What is the primary function of interferon in the immune system?
What is the primary function of interferon in the immune system?
Which immune-mediated condition arises when the immune system mistakenly attacks its own body?
Which immune-mediated condition arises when the immune system mistakenly attacks its own body?
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What is a significant challenge faced when the immune system encounters neurons in the CNS?
What is a significant challenge faced when the immune system encounters neurons in the CNS?
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What is the primary function of B-cells?
What is the primary function of B-cells?
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Where do T-cells mature?
Where do T-cells mature?
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Which type of pathogens do T-cells primarily target?
Which type of pathogens do T-cells primarily target?
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What role do helper T-cells (CD4+ cells) play in immune responses?
What role do helper T-cells (CD4+ cells) play in immune responses?
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What is the function of antibodies in the immune response?
What is the function of antibodies in the immune response?
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How do B-cells recognize pathogens?
How do B-cells recognize pathogens?
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Which cytokine-secreting T-cell subtype activates macrophages?
Which cytokine-secreting T-cell subtype activates macrophages?
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What is the role of Mucosa Associated Lymphoid Tissue (MALT)?
What is the role of Mucosa Associated Lymphoid Tissue (MALT)?
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In which part of the immune system do B-cells proliferate and mature?
In which part of the immune system do B-cells proliferate and mature?
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What happens when a B-cell is activated by a T-helper cell?
What happens when a B-cell is activated by a T-helper cell?
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What is the primary type of T-cell responsible for killing infected cells?
What is the primary type of T-cell responsible for killing infected cells?
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What is indicated by the term 'Class 1 MHC' related to T-cells?
What is indicated by the term 'Class 1 MHC' related to T-cells?
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What determines the type of immune response generated (TH1 or TH2)?
What determines the type of immune response generated (TH1 or TH2)?
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Which type of antibody is most abundant in the blood and provides maternal protection during neonatal life?
Which type of antibody is most abundant in the blood and provides maternal protection during neonatal life?
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What is a key feature of Class 1 MHC molecules?
What is a key feature of Class 1 MHC molecules?
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Which antibody class is primarily responsible for protection at mucosal surfaces?
Which antibody class is primarily responsible for protection at mucosal surfaces?
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What type of hypersensitivity reaction is mainly mediated by TH1 responses?
What type of hypersensitivity reaction is mainly mediated by TH1 responses?
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What is the role of the Fc region of antibodies?
What is the role of the Fc region of antibodies?
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Which antibody class indicates a recent infection or exposure to an antigen when elevated?
Which antibody class indicates a recent infection or exposure to an antigen when elevated?
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The term HUMAN LEUKOCYTE ANTIGEN refers to what aspect of the immune system?
The term HUMAN LEUKOCYTE ANTIGEN refers to what aspect of the immune system?
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Which antibody is primarily involved in Type 1 hypersensitivity reactions?
Which antibody is primarily involved in Type 1 hypersensitivity reactions?
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Which of the following statements about Class 2 MHC molecules is correct?
Which of the following statements about Class 2 MHC molecules is correct?
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What is not a function of IgG antibodies?
What is not a function of IgG antibodies?
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Contact dermatitis is primarily associated with which immune response?
Contact dermatitis is primarily associated with which immune response?
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Which class of antibody is not well understood in terms of its function?
Which class of antibody is not well understood in terms of its function?
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Which of the following is a primary defense against local respiratory or gastrointestinal infections?
Which of the following is a primary defense against local respiratory or gastrointestinal infections?
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Which immune response relies on macrophages presenting antigens to TH1 cells?
Which immune response relies on macrophages presenting antigens to TH1 cells?
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Which type of hypersensitivity reaction involves the release of histamine, leukotrienes, and prostaglandins?
Which type of hypersensitivity reaction involves the release of histamine, leukotrienes, and prostaglandins?
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What is the primary immunoglobulin involved in Type 1 hypersensitivity reactions?
What is the primary immunoglobulin involved in Type 1 hypersensitivity reactions?
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Which of the following is NOT a typical action of histamine in a Type 1 hypersensitivity reaction?
Which of the following is NOT a typical action of histamine in a Type 1 hypersensitivity reaction?
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Which ocular manifestation is associated with Type 1 hypersensitivity reactions?
Which ocular manifestation is associated with Type 1 hypersensitivity reactions?
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What is anaphylaxis?
What is anaphylaxis?
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Which antibodies are primarily involved in Type 2 hypersensitivity reactions?
Which antibodies are primarily involved in Type 2 hypersensitivity reactions?
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In Type 2 hypersensitivity reactions, antibodies target antigens located on:
In Type 2 hypersensitivity reactions, antibodies target antigens located on:
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What is a characteristic feature of ocular pemphigoid in the context of Type 2 hypersensitivity?
What is a characteristic feature of ocular pemphigoid in the context of Type 2 hypersensitivity?
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Which type of hypersensitivity involves the deposition of antigen-antibody complexes in tissue?
Which type of hypersensitivity involves the deposition of antigen-antibody complexes in tissue?
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In Type 3 hypersensitivity, the deposited immune complexes cause tissue damage primarily through:
In Type 3 hypersensitivity, the deposited immune complexes cause tissue damage primarily through:
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Which ocular condition is associated with Type 3 hypersensitivity?
Which ocular condition is associated with Type 3 hypersensitivity?
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What is a common location for immune complex deposition in Type 3 hypersensitivity reactions?
What is a common location for immune complex deposition in Type 3 hypersensitivity reactions?
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Which of these is NOT a typical symptom of anaphylaxis?
Which of these is NOT a typical symptom of anaphylaxis?
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Which of the following best describes the timing of a Type 1 hypersensitivity reaction manifestation?
Which of the following best describes the timing of a Type 1 hypersensitivity reaction manifestation?
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Which is a typical response of the eye to a Type 1 hypersensitivity reaction?
Which is a typical response of the eye to a Type 1 hypersensitivity reaction?
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Where does the differentiation of lymphocytes into B-cells and T-cells occur?
Where does the differentiation of lymphocytes into B-cells and T-cells occur?
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What is the primary function of lymph nodes in the adaptive immune response?
What is the primary function of lymph nodes in the adaptive immune response?
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Which of the following is NOT a characteristic of the adaptive immune response?
Which of the following is NOT a characteristic of the adaptive immune response?
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What is the role of memory cells in the adaptive immune response?
What is the role of memory cells in the adaptive immune response?
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During which phase of the immune response do lymphocytes travel to the site of infection?
During which phase of the immune response do lymphocytes travel to the site of infection?
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What is the process of clonal selection?
What is the process of clonal selection?
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Where does clonal expansion of lymphocytes occur?
Where does clonal expansion of lymphocytes occur?
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Which of the following cells is NOT involved in the adaptive immune response?
Which of the following cells is NOT involved in the adaptive immune response?
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What is the primary function of the surface barrier in the immune system?
What is the primary function of the surface barrier in the immune system?
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Which characteristic distinguishes the adaptive immune system from the innate immune system?
Which characteristic distinguishes the adaptive immune system from the innate immune system?
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The recruitment of cells to an area of infection is mediated by which substances?
The recruitment of cells to an area of infection is mediated by which substances?
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What role do dendritic cells play in the immune system?
What role do dendritic cells play in the immune system?
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Increased vascular permeability during inflammation is primarily due to the action of which component?
Increased vascular permeability during inflammation is primarily due to the action of which component?
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Which cells are primarily responsible for defending against extracellular bacteria?
Which cells are primarily responsible for defending against extracellular bacteria?
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What is the main role of natural killer (NK) cells?
What is the main role of natural killer (NK) cells?
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What is the function of the complement system in the immune response?
What is the function of the complement system in the immune response?
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Which type of immunity is not fully functional at birth?
Which type of immunity is not fully functional at birth?
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Which of the following cells has a short lifespan and is primarily involved in immediate response to infection?
Which of the following cells has a short lifespan and is primarily involved in immediate response to infection?
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In which scenario would the adaptive immune response be specifically triggered?
In which scenario would the adaptive immune response be specifically triggered?
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What do mast cells release when activated that contributes to inflammation?
What do mast cells release when activated that contributes to inflammation?
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What form of cell death is primarily caused by natural killer cells?
What form of cell death is primarily caused by natural killer cells?
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What is the main distinction between phagocytosis and apoptosis?
What is the main distinction between phagocytosis and apoptosis?
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Study Notes
Immune System Overview
- Three barriers with increasing specificity: surface barriers (skin, eyelashes); chemical (low stomach pH), mechanical (coughing, sneezing), and biological (tears, urine, lysosomes, phospholipase A2)
- Innate Immune System: rapid, non-specific, no memory, determined by genetics and age, first line of defense
- Adaptive Immune System: slow, specific, with memory, cell-mediated and humoral
- Innate immune cells involved in inflammation include mast cells and basophils: increased blood flow, increased vascular permeability, increased cell recruitment
- Complement System (C1-C9): initiates recruitment of inflammatory cells, labels pathogens for destruction, disrupts plasma membranes of infected cells, and removes antibody-antigen complexes
Innate Immune System Cells
- NK Cells: kill tumor and viral cells, using perforin and granzymes which cause apoptosis
- Mast Cells: associated with allergies and anaphylaxis, release histamine and heparin, involved in vasodilation and recruiting other cells
- Macrophages: phagocytes, swallow pathogens and form phagosomes, can remove damaged and old cells
- Dendritic Cells: antigen presenting cells, process foreign material, and present to lymphocytes
- Neutrophils: short-lived, toxic molecules (e.g. reactive oxygen species), important in defense against extracellular bacteria
- Basophils and Eosinophils: related to neutrophils, release histamine, important in defense against parasites and allergic reactions
Adaptive Immune System
- The adaptive immune response is slower, takes minutes/hours, only present in vertebrates. Memory cells lead to a greater subsequent response with repeat encounters.
- Adaptive immune cells: B cells and T cells
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B Cells: bone marrow derived, mature in bone marrow, secrete antibodies, identify pathogens and take up antigen-antibody complexes. They process the complex into peptides and present on MHC Class 2 molecules to attract T-helper cells
- Humoral immunity is mediated by these B cells
- T Cells: thymus derived, mature in thymus, destroy virus-infected cells (cytotoxic T cells -CD8+) and control the type of immune response (helper T cells -CD4+ ), TH1 activates macrophages and TH2 promote antibody responses
- Clonal Selection: lymphocytes diversify and have own antigen-specificity
- Clonal Expansion: lymphocytes that recognise a particular pathogen divide rapidly in the secondary lymphoid tissues
- Two phases of immune response: initiation (afferent) is in the mucosa/local lymph nodes near the infection site; effector phase is when lymphocytes and phagocytes enter the infection site
Antibody-Mediated Response
- Basic structure: two light chains and two heavy chains.
- Antigen-binding sites, and fragment that binds to receptors on cells or complement system.
- 5 classes of antibodies, each with unique structure, function, and location: IgG, IgA, IgM, IgE, and IgD.
- IgG: most abundant, transferred across placenta, opsonisation.
- IgA: found in secretions, primary defense against infections in respiratory/GI tracts
- IgM: First antibody produced in an immune response, activates complement.
- IgE: binds to mast cells and basophils, involved in allergic reactions.
- IgD: role unclear.
Immune Defense Mechanisms (Bacteria)
- Releasing toxins
- Invading tissues—parasitizing and killing cells
- Combination of the above.
Immune Defense Mechanisms (Viruses)
- Interferons
- Cytotoxic T cells
- Various activation processes for infected cells and targeting.
Types of Hypersensitivity
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Type 1 Allergy: rapid, localized or generalized reaction (e.g., asthma, hayfever)
- Mediated by IgE antibodies and mast/basophil cells. Involvement of histamine is key.
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Type 2 Cytotoxic: antibodies target cells—causes cell damage.
- Antibody-mediated destruction of cells and tissues (e.g., blood transfusion reactions).
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Type 3 Immune Complex: formation and deposition in tissues—causing inflammation.
- Immune complexes deposited in tissues cause inflammation and damage (e.g., glomerulonephritis).
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Type 4 Delayed: T cells—causing tissue damage via cytokines
- Cell-mediated response, tissue injury mediated by cytokines. Examples include contact dermatitis.
Lymphocytes (and other cells) and Tissues
- Lymphoid follicles: areas in the lymph nodes where B cells proliferate, develop, and mature antibodies
- Para cortex: an area where T cells activate other B cells
- Mucosa-associated lymphoid tissue (MALT): a major site of pathogen entry
- Important for immune surveillance in mucosal surfaces—protection against pathogens that enter via the mucous membranes (e.g., respiratory, digestive)
MHC Molecules
- MHC class I: on all cells, present self-antigens.
- MHC class II: on APC, presents foreign antigens.
Immunodeficiency
- Genetic or acquired inability to fight infections effectively.
- Ability of the body to effectively mount an immune response against infections is compromised.
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Description
Explore the intricate workings of the immune system, focusing on both innate and adaptive responses. This quiz covers crucial components such as innate immune cells, the complement system, and the barriers protecting the body against pathogens.
