Questions and Answers
Which immune cells are primarily stimulated by interferons to enhance host defenses?
What is one of the main roles of antibodies in the immune response?
Which pathway of the complement system is activated by antibody-antigen complexes?
What type of antibodies do beta cells primarily produce?
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Which cytokine is primarily produced by Th1 T-cells?
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Which of the following cells is NOT considered an antigen-presenting cell (APC)?
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What type of T-cells interact with MHC Class II molecules?
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What role does opsonization play in the immune response?
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Which of the following statements best describes the function of memory cells?
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Which type of receptor is involved in detecting viral RNA?
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The shallow groove of MHC Class II molecules is designed to bind what length of peptides?
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What is the primary function of interferons in the immune response?
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Which group of cytokines specifically increases natural killer cell production?
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Which symptom is most commonly associated with the action of interferons on the immune system?
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Which type of immune response involves the activation of plasma cells?
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Nod-like Receptors (NLRs) are crucial for recognizing which type of molecular patterns?
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Which type of interferon is NOT involved in enhancing antiviral responses?
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What is the primary function of CD8 Cytotoxic T-cells in the immune system?
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Which mechanism does the complement system NOT directly promote?
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The primary role of Toll-like Receptors (TLRs) is to recognize which of the following?
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What is the primary function of the Fab region of an antibody?
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Which type of antibody is primarily involved in allergic reactions?
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In which type of hypersensitivity reaction is immune complex deposition a primary mechanism?
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What is the primary result of the activation of CD4 T-helper cells during HIV infection?
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Which of the following correctly describes the difference between primary and secondary antibody responses?
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What kind of hypersensitivity reaction involves T lymphocytes releasing cytokines upon second exposure?
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Which of the following antibodies has the highest number of binding sites?
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What mechanism describes antibody-mediated destruction of cell surface antigens?
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What characterizes the diagnosis of AIDS?
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Which mechanism of Type 1 hypersensitivity leads to allergic symptoms?
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What distinguishes adaptive immunity from innate immunity?
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Which of the following correctly describes a component of the innate immune system?
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What is the primary function of dendritic cells in the immune response?
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How do natural killer cells contribute to the immune response?
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Which of the following factors triggers the innate immune response?
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What is the role of cytokines in the inflammatory response?
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Which immune response is primarily mediated by T-cells?
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What mechanism do phagocytic cells use to eliminate pathogens?
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Which cytokine type assists in attracting white blood cells to sites of infection?
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What is a feature of immunological memory in the adaptive immune system?
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Study Notes
Introduction to Immunity
- Immunity consists of two main types: Innate and Adaptive immunity.
- Innate immunity is present from birth and provides a quick response, while adaptive immunity develops later, learned through exposure, and offers a slower response.
Components of the Immune Systems
Innate Immune System
- Physical Barriers: Includes skin, gastrointestinal tract, respiratory tract, nasopharynx, cilia, eyelashes, and body hair.
- Chemical Barriers: Consists of secretions such as mucus, bile, gastric acid, saliva, tears, and sweat.
- Cellular Components: Comprises phagocytic leukocytes, dendritic cells, and natural killer cells.
- Proteins: Involves plasma proteins, complement proteins, and cytokines (e.g., tumor necrotic factor, granzymes).
Adaptive Immune System
- Cells: Predominantly B lymphocytes (beta cells) and T cells.
- Responses: Includes cell-mediated immunity by T cells and humoral immunity by B cells through antibody production.
Key Differences
- Innate Immunity: Triggered by broad molecular patterns, involves immediate responses, and is protein-dependent (e.g., cytokines).
- Adaptive Immunity: Triggered by specific events, particularly upon second exposure, relies on T-cells and B-cells, and features immunological memory.
Immune System Players
Dendritic Cells
- Act as sentinels and are the most potent antigen-presenting cells, initiating adaptive responses.
Natural Killer Cells
- Recognize and kill virus-infected and tumor cells using granzyme and perforin.
- Engage in antibody-dependent cellular cytotoxicity (ADCC) and produce gamma interferon.
Phagocytic Cells
- Include monocytes, macrophages, and polymorphonuclear leukocytes (PMNs).
- Perform phagocytosis, digestion, and processing of foreign proteins.
Cytokines and Inflammatory Response
- Cytokines: Small proteins crucial for cell signaling, interacting with specific receptors on target cells.
- Types: Involve signaler types (e.g., tumor necrotic factor, interleukins) and chemokines that attract white blood cells.
- Inflammatory Response: Mediated by cytokines and leads to microvessel dilation, edema, and enhanced immune cell recruitment.
Complement System
- Function: Enhances antibody and phagocytic cell functions, promotes inflammation, pathogen lysis, and opsonization.
- Components: Over 30 proteins found in serum or on cell membranes.
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Pathways:
- Classical Pathway: Activated by antibody-antigen complexes.
- Alternative Pathway: Activated by foreign materials.
- Lectin Pathway: Activated by mannose-binding lectin on bacterial surfaces.
Antigen Presentation
- Antigen-Presenting Cells (APCs): Include dendritic cells, macrophages, and B lymphocytes that present antigens via Major Histocompatibility Complex (MHC) proteins, essential for T-cell activation.
Opsins and Phagocytosis
- Opsins: Extracellular proteins (e.g., immunoglobulin G, mannose-binding lectin) that tag cells for phagocytosis.
- Opsinization: Process whereby antibodies or complement proteins coat pathogens to enhance phagocytosis.
Microbial Sensing Proteins
- Toll-like Receptors (TLRs): Early immune recognition receptors that detect pathogen-associated molecular patterns (PAMPs).
- Nod-like Receptors (NLRs): Intracellular sensors recognizing PAMPs and damage-associated molecular patterns (DAMPs).
- RIG-1-like Receptors (RLRs) and MDA5: Detect viral RNA and play roles in initiating antiviral responses.
Interferons and Cytokines
- Function: Released by virus-infected cells, they induce nearby cells to enhance antiviral defenses.
- Types: Include Alpha, Beta, Gamma, all inhibiting viral growth.
- Effects: Stimulate immune cells, causing flu-like symptoms during an immune response.
Adaptive Immune System
- Known as the acquired immune system, it involves specialized cells for pathogen elimination and establishes immunological memory for enhanced future responses.
Antibodies and Beta Cells
- Role: Long-lasting protection against pathogens.
- Types: Include antibodies produced by beta cells and T-cells.
- Humoral Response: Involves beta cell activation, plasma cell proliferation, and memory cells.
T-Cells
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Types:
- CD4 Helper T-Cells activate other immune cells.
- CD8 Cytotoxic T-Cells kill infected cells.
- Subtypes: Include Th1, Th2, Th17, and T-Regulatory cells, each with distinct cytokine production and immune regulation roles.
Antigen Recognition and MHC Molecules
- Epitope: Part of an antigen recognized by the immune system.
- MHC Class I: Binds peptides of 8-10 amino acids, crucial for presenting antigens to CD8 T-cells.
- MHC Class II: Binds longer peptides of 13-17 amino acids for CD4 T-cell recognition.
Antibody Structure and Response
- Structure: Y-shaped proteins with variable (antigen-binding) and constant regions.
- Types: Include IgA, IgD, IgE, IgG, and IgM, varying by binding sites and functions.
- Antibody Functions: Neutralization, opsonization, agglutination, complement fixation, and precipitation.
Hypersensitivity Reactions
- Type 1: Involves IgE and mast cell/eosinophil degranulation.
- Type 2: Antibody-mediated destruction of cell surface antigens.
- Type 3: Immune complex deposition causing inflammation.
- Type 4: Delayed hypersensitivity mediated by T lymphocytes.
AIDS and Immune Deficiency
- HIV targets CD4 T-helper cells, leading to progressive immune impairment.
- AIDS is diagnosed at advanced stages characterized by significant opportunistic infections or severely low CD4 counts.
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Description
This quiz explores the fundamental concepts of innate and adaptive immunity. It covers crucial components such as physical and chemical barriers that form the innate immune system, as well as the characteristics and development of adaptive immunity. Test your knowledge on how these two systems work together to protect the body.
