Innate and Adaptive Immunity

Chapter 15: Innate Immunity

Chapter Summary

  • Pages: 467-468

Suggested Readings

  • Introduction and an Overview of the Body’s Defenses - pg. 447

  • The Body’s First Line of Defense - pgs. 447-451

  • The Body’s Second Line of Defense - pgs. 452-466

Terminology

  • Innate Immunity: A non-specific defense mechanism present from birth, providing immediate protection against infectious agents.

  • Competitive Inhibition: A process in which a substance competes with the actual substrate for the active site of an enzyme.

  • Sebum: An oily secretion produced by sebaceous glands that helps to prevent the growth of bacteria and fungi on the skin.

  • Formed Elements: Components of blood including cells and cell fragments such as red blood cells, white blood cells, and platelets.

  • Plasma: The liquid component of blood that transports cells, nutrients, hormones, and waste products.

  • Platelets: Small cell fragments in the blood that are involved in clotting.

  • Phagocyte: A type of cell capable of engulfing and absorbing bacteria and other small cells and particles.

  • Lysozyme: An enzyme that breaks down the cell wall of bacteria, contributing to the immune response.

  • Leukocytes: White blood cells that are involved in protecting the body against both infectious diseases and foreign invaders.

  • Granulocytes: A type of leukocyte characterized by the presence of granules in their cytoplasm; includes neutrophils, eosinophils, and basophils.

  • Agranulocytes: Leukocytes without granules in their cytoplasm; includes lymphocytes and monocytes.

  • Phagosome: A vesicle formed around a particle engulfed by a phagocyte.

  • Eosinophil: A type of granulocyte that primarily combats parasites and is involved in allergic reactions.

  • Basophil: A granulocyte that releases histamine and plays a role in inflammatory responses.

  • Neutrophil: A type of phagocyte and the most abundant type of white blood cell, primarily involved in responding to infections.

  • Monocytes: A type of agranulocyte that differentiates into macrophages and dendritic cells in tissues.

  • Phagolysosome: A cellular organelle formed by the fusion of a phagosome and a lysosome, where degradation of engulfed material occurs.

  • Interferon: A group of signaling proteins made and released by host cells in response to infection, particularly by viruses.

  • Inflammation: A biological response to harmful stimuli, characterized by redness, heat, swelling, and pain.

  • NK Cells (Natural Killer Cells): A type of lymphocyte that plays a role in the innate immune response by targeting and destroying infected or cancerous cells.

  • Fever: An increase in body temperature, often a response to infection, which can inhibit pathogen growth.

  • Pyrogens: Substances that induce fever.

  • Toll-like Receptors (TLRs): A class of proteins that play a key role in the innate immune system by recognizing pathogens and activating immune responses.

  • Complement System: A complex system of proteins that enhances the ability of antibodies and phagocytic cells to clear pathogens from an organism.

  • Acute Inflammation: A rapid and short-term response to injury or infection, characterized by the influx of neutrophils.

  • Chronic Inflammation: A prolonged inflammatory response that often involves a progressive shift in the types of cells at the site of inflammation.

Learning Objectives (Innate Immunity)

  1. Compare and Contrast Innate and Adaptive Immunity:

    • Innate immunity: Rapid, non-specific response, includes barriers, phagocytes, and inflammation.

    • Adaptive immunity: Slower, specific response, involves lymphocytes, antibodies, and memory.

  2. Analyze Skin and Mucous Membranes in Innate Immunity:

    • Skin: Acts as a physical barrier, secretes antimicrobial substances like sebum.

    • Mucous membranes: Trap pathogens and contain antimicrobial agents.

  3. Identify Physical and Chemical Factors of 1st Line of Defense:

    • Physical factors: Skin, mucous membranes, hair, and cilia.

    • Chemical factors: Saliva, tears (lysozyme), gastric acid, and sebum.

  4. Classify Mechanisms of Innate Immunity as 1st or 2nd Lines of Defense:

    • 1st line: Physical and chemical barriers (skin, mucous).

    • 2nd line: Phagocytosis, inflammation, fever, and the complement system.

  5. Evaluate Role of Normal Microbiota in Innate Immunity:

    • Normal microbiota outcompete pathogens for resources and produce substances that inhibit pathogen growth.

  6. Classify Roles of Various Leukocytes in Immunity:

    • Neutrophils: First responders to infection.

    • Eosinophils: Deal with parasitic infections.

    • Basophils: Involved in allergic responses.

    • Monocytes: Differentiate into macrophages and dendritic cells for phagocytosis.

  7. Analyze Stages of Phagocytosis:

    • 1. Chemotaxis

    • 2. Adherence

    • 3. Ingestion (engulfing)

    • 4. Fusion with lysozyme (forming phagolysosome)

    • 5. Digestion (breakdown of pathogen)

    • 6. Exocytosis (removal of debris)

  8. Know Components of Second Line of Defense:

    • Phagocytes, inflammation, fever, complement proteins, and cytokines.

Chapter 16: Adaptive Immunity

Chapter Summary

  • Pages: 498-499

Suggested Readings

  • Introduction and Overview of Adaptive Immunity - pgs. 473-474

  • Elements of Adaptive Immunity - pgs. 474-489

  • Cell-mediated Immune Responses - pgs. 489-492

  • Antibody Immune Responses - pgs. 492-495

  • Types of Acquired Immunity - pgs. 495-496

Terminology

  • Adaptive Immunity: A specific immune response that develops over time and establishes immunological memory.

  • Humoral Immune Response: The aspect of immunity that is mediated by macromolecules found in extracellular fluids, primarily antibodies.

  • Cell-mediated Immune Response: The immune response that does not involve antibodies but rather the activation of phagocytes and T cells.

  • Lymph: The fluid that circulates through the lymphatic system, transporting immune cells and antigens.

  • Lymph Nodes: Structures that filter lymph and house immune cells, facilitating the immune response.

  • Antigen: A substance that induces an immune response.

  • Exogenous Antigen: Antigens originating outside the body.

  • Endogenous Antigen: Antigens produced within the body, such as those from viruses or cancer cells.

  • Autoantigen: Antigens that are recognized by the immune system as a normal component of the body.

  • Major Histocompatibility Complex (MHC): A set of cell surface proteins essential for the acquired immune system to recognize foreign molecules.

  • Antigen-Presenting Cell (APC): Cells that display exogenous antigens, causing T cells to respond.

  • Epitopes: Specific sites on an antigen recognized by antibodies or T-cell receptors.

  • T Cell Receptor: A molecule on the surface of T cells that recognizes antigens presented by APCs.

  • Cytotoxic T Cells: T cells that kill virus-infected cells and cancer cells.

  • Helper T Cells: T cells that help stimulate B cells and cytotoxic T cells.

  • Regulatory T Cells: T cells that maintain tolerance to self-antigens and prevent autoimmune disease.

  • B Lymphocytes: A type of white blood cell involved in humoral immunity, responsible for producing antibodies.

  • Immunoglobulins: Antibodies produced by B cells to identify and neutralize pathogens.

  • Antibody: A protein produced by plasma cells that can bind to specific antigens.

  • Fab Region: The fragment of an antibody responsible for antigen recognition.

  • Fc Region: The fragment of an antibody that interacts with cell surface receptors and complement proteins.

  • Agglutination: The clumping of particles (e.g., bacteria) in response to an antibody.

  • Opsonin: Molecules that enhance phagocytosis of antigens by marking them for destruction.

  • Neutralization: The process by which antibodies render a pathogen non-infectious.

  • Antibody Immune Response: The response of B cells to produce antibodies against specific antigens.

  • Acquired Immunity: Immunity gained through exposure to antigens, leading to memory formation.

  • IgM, IgG, IgA, IgE, IgD: The five major classes of immunoglobulins, each with specific roles and characteristics.

  • Cytokines: Signaling molecules that mediate and regulate immunity, inflammation, and hematopoiesis.

  • Memory Cells: Long-lived B or T cells that can quickly respond to a previously encountered antigen.

Learning Objectives (Adaptive Immunity)

  1. Know Humoral and Cellular Immunity:

    • Humoral: Involves B cells, antibodies.

    • Cellular: Involves T cells and the recognition of infected or abnormal cells.

  2. Know Classes of Antibodies:

    • IgM: First antibody produced in response, effective in forming complexes.

    • IgG: Most abundant, crosses placenta, protects against bacterial and viral infections.

    • IgA: Found in mucosal areas, protects against pathogens in secretions (saliva, tears).

    • IgE: Involved in allergic reactions and responses to parasitic infections.

    • IgD: Functions primarily as a receptor on B cells.

  3. Compare T Helper, T Cytotoxic, and T Regulatory Cells:

    • T Helper Cells: Activate B cells and cytotoxic T cells, regulate immune responses.

    • T Cytotoxic Cells: Directly kill infected or cancerous cells.

    • T Regulatory Cells: Suppress immune responses to maintain tolerance.

  4. Identify Five Outcomes of Antigen-Antibody Reaction:

    • Neutralization, agglutination, opsonization, activation of complement, and inflammation.

  5. Analyze Primary and Secondary Immune Responses:

    • Primary: First exposure results in slow response, memory cells are formed.

    • Secondary: Subsequent exposures lead to a quicker and stronger response due to memory cells.