Immunology: Primary vs. Secondary Responses
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What characterizes secondary immune responses compared to primary immune responses?

  • They are usually more rapid and larger. (correct)
  • They are slower and less effective.
  • They generate fewer memory cells.
  • They involve only B lymphocytes.

    • What is a primary role of antigen presenting cells (APCs)?

  • To activate only B lymphocytes.
  • To display antigens to lymphocytes. (correct)
  • To produce antibodies for all types of pathogens.
  • To destroy infected cells directly.

    • Which cells are considered the most effective APCs for activating naïve T cells?

  • Dendritic cells. (correct)
  • B lymphocytes.
  • Macrophages.
  • Memory T cells.

    • What is the function of co-stimulators in T cell activation?

    <p>To provide additional signals along with antigens.</p> Signup and view all the answers

    How do memory B lymphocytes compare to naïve B lymphocytes in antibody production?

    <p>They produce antibodies that bind antigens with higher affinities.</p> Signup and view all the answers

    What role do adjuvants play in immune responses?

    <p>They enhance the immune response by stimulating APC functions.</p> Signup and view all the answers

    In what way do memory T cells differ from naïve T cells during antigen challenge?

    <p>They react more rapidly and vigorously.</p> Signup and view all the answers

    Where can dendritic cells sample antigens that enter the bloodstream?

    <p>In the spleen and from circulating DCs.</p> Signup and view all the answers

    What is the primary function of CTLA-4-Ig as a therapeutic agent?

    <p>To block inhibitory receptors in immune responses</p> Signup and view all the answers

    Which type of T cell is responsible for recognizing antigens of cytoplasmic microbes and killing infected cells?

    <p>CD8+ cytotoxic T lymphocytes</p> Signup and view all the answers

    What effect does IFN-γ have on the differentiation of CD4+ T cells?

    <p>Inhibits development of Th2 and Th17 cells</p> Signup and view all the answers

    In the context of T cell activation, which of the following is enhanced by Th1 cells?

    <p>Recruitment of leukocytes</p> Signup and view all the answers

    How do antibodies that block PD-1 function in cancer immunotherapy?

    <p>Prevent PD-1 from binding its ligands</p> Signup and view all the answers

    What common function do Th2 cells serve in immune responses?

    <p>Regulate B cell antibody production</p> Signup and view all the answers

    Which cytokine is primarily produced by Th1 cells to activate macrophages?

    <p>IFN-γ</p> Signup and view all the answers

    Which therapeutic strategy is under clinical trials for transplant rejection?

    <p>Inhibitors of the CD40L:CD40 pathway</p> Signup and view all the answers

    What primary issue arises from the complexity of molecules produced by living cells in biotherapeutics?

    <p>They exhibit batch-to-batch variation.</p> Signup and view all the answers

    What is the main consequence of immunogenicity in therapeutic proteins?

    <p>Formation of Anti-Drug Antibodies (ADA).</p> Signup and view all the answers

    Which of the following describes binding Anti-Drug Antibodies (ADA)?

    <p>They may impact pharmacokinetics and safety.</p> Signup and view all the answers

    What determines the immunogenicity of protein antigens according to the provided information?

    <p>The nature of the dendritic cell displaying antigens.</p> Signup and view all the answers

    What role do tolerogenic antigens play in the immune system?

    <p>They are recognized by immature lymphocytes.</p> Signup and view all the answers

    Which statement accurately reflects the FDA's approach to immunogenicity for biotherapeutics?

    <p>All biotherapeutics address immunogenicity within Section 6.2 of their label.</p> Signup and view all the answers

    What is the typical immune response when a mouse antibody is injected into a human patient?

    <p>Formation of human anti-mouse antibodies (HAMA).</p> Signup and view all the answers

    What can be a potential effect of high immunogenicity in therapeutic proteins?

    <p>Increased risk of adverse reactions.</p> Signup and view all the answers

    What effect does increasing the human content of the primary amino acid sequence have on immunogenicity?

    <p>It decreases immunogenicity.</p> Signup and view all the answers

    Why are mAbs with mouse Fc eliminated more rapidly from the body?

    <p>They are recognized as non-human by the immune system.</p> Signup and view all the answers

    Which route of administration is likely to be more immunogenic?

    <p>Intramuscular injections.</p> Signup and view all the answers

    How does dosing frequency correlate with immunogenicity?

    <p>Higher immunogenicity leads to more frequent dosing.</p> Signup and view all the answers

    What happens to proteins after subcutaneous or intramuscular dosing before reaching systemic circulation?

    <p>They travel through lymph nodes.</p> Signup and view all the answers

    What might contribute to the development of autoimmune diseases?

    <p>Activation of antigen-presenting cells (APCs)</p> Signup and view all the answers

    Which of the following is NOT considered a therapeutic target for autoimmune disorders?

    <p>Hormonal levels</p> Signup and view all the answers

    What is the main purpose of disease modifying anti-rheumatic drugs (DMARDs)?

    <p>To slow disease progression</p> Signup and view all the answers

    Which type of DMARDs include agents like Methotrexate and Leflunomide?

    <p>Conventional synthetic DMARDs</p> Signup and view all the answers

    What is the role of NSAIDs and steroids in the treatment of autoimmune diseases?

    <p>They treat symptoms without modifying disease progression</p> Signup and view all the answers

    Which statement accurately describes biosimilars in relation to biological DMARDs?

    <p>They are generic versions of original biological agents.</p> Signup and view all the answers

    Selection of the optimal therapeutic target for autoimmune diseases primarily depends on what factor?

    <p>Disease pathology and characteristics</p> Signup and view all the answers

    How do B cell depleting monoclonal antibodies typically function?

    <p>By inhibiting the production of autoantibodies</p> Signup and view all the answers

    What is one of the mechanisms by which Rituximab leads to the death of CD20-expressing B cells?

    <p>Direct lysis</p> Signup and view all the answers

    Which is NOT a mechanism of action for IVIG in autoimmune conditions?

    <p>Increased production of pro-inflammatory cytokines</p> Signup and view all the answers

    What type of hypersensitivity reaction is characterized by harmful immune responses against environmental antigens?

    <p>Type I hypersensitivity</p> Signup and view all the answers

    Which of the following actions is a mechanism attributed to Rituximab?

    <p>Antibody-dependent cellular cytotoxicity</p> Signup and view all the answers

    Which statement regarding IVIG's function is correct?

    <p>It may alter effector mechanisms towards an anti-inflammatory response.</p> Signup and view all the answers

    What does Rituximab mainly target in immunological therapy?

    <p>CD20-expressing B cells</p> Signup and view all the answers

    In the context of autoimmune diseases, what is a likely outcome of reduced circulating B cells due to Rituximab?

    <p>Reduced B cell-dependent autoimmunity</p> Signup and view all the answers

    Which class of hypersensitivity includes reactions to drugs and microbes?

    <p>Type I hypersensitivity</p> Signup and view all the answers

    Study Notes

    Immune System & Immunology - Fundamental Principles

    • This presentation covers fundamental principles of the immune system and immunology, particularly relevant to pharmaceutical sciences.
    • The immune system is a complex system of interconnected systems within the body.
    • Key characteristics of the immune system include specificity, diversity, memory, homeostasis, and tolerance.
    • The immune system has several functions, including a barrier function, tolerance, pathogen clearance, and chronic inflammation.
    • Adaptive immunity comprises humoral and cell-mediated immunity.
    • Humoral immunity involves B lymphocytes secreting antibodies to prevent and eliminate extracellular microbes.
    • Cell-mediated immunity involves helper T lymphocytes activating macrophages or cytotoxic T lymphocytes directly destroying infected cells.
    • Humoral and cell-mediated immunity are aspects of adaptive immunity, mediated by macromolecules like antibodies, complement proteins, and antimicrobial peptides in extracellular fluids.
    • Cellular immunity involves antigen recognition, activation of macrophages, initiation/differentiation of T & B cells, and pathogen killing.
    • The immune system is composed of innate and adaptive immunity. Innate immunity acts early in response.
    • Innate immunity relies on cellular and chemical barriers, secreted proteins, and cells like phagocytes, dendritic cells, NK cells, mast cells, and innate lymphoid cells.
    • Every individual's immune system recognizes, responds to, and eliminates foreign antigens, but does not usually react against self antigens.
    • Immune cells (e.g., macrophages, neutrophils, dendritic cells, mast cells, basophils, eosinophils) have specific roles in immunity (phagocytosis, killing, inflammation).
    • Lymphocytes (B cells, helper T cells, cytotoxic T cells, regulatory T cells, NK cells) are crucial in adaptive immunity with distinct functions (neutralization, activation, killing, suppression, killing).
    • Immune system cells derive from hematopoietic stem cells (HSCs) in the bone marrow, which are pluripotent and self-renewing.
    • Innate and adaptive immunity work together to defend against pathogens.
    • Adaptive immunity (responding to pathogens) is stimulated by exposure to pathogens, is specific for each pathogen, and has memory.
    • Clonal expansion is essential for effective adaptive immunity response, increasing the number of specific immune cells for a pathogen.
    • Memory in adaptive immunity allows a faster and stronger response to subsequent encounters with the same pathogen.
    • Antigen-presenting cells (APCs) are specialized cells that display antigens to T lymphocytes (activating T cells).
    • Dendritic cells, macrophages, and B cells are key APCs.
    • Costimulatory molecules on APCs are crucial for T cell activation.
    • Lymphocyte development is a complex process with sequential stages.
    • Multipotent stem cells give rise to distinct B and T lineages.
    • Checkpoints in lymphocyte maturation ensure the production of functional lymphocytes without self-reactivity.
    • T cell maturation in the thymus involves positive and negative selection to eliminate self-reactive T cells.
    • T cell activation by antigen presentation is a key process in adaptive immunity, leading to effector function.
    • Different types of CD4+ effector T cells have distinct functions (Th1, Th2, Th17, Tfh) in immune responses.
    • Different subsets of CD4+ effector T cells are induced by and protect against different microbes in the intestinal mucosa.
    • Autoimmune diseases occur when the immune system mistakenly attacks the body's own tissues.
    • Several factors contribute to the development of autoimmunity.
    • Therapies for autoimmune diseases aim to dampen the aberrant immune response.
    • Disease-modifying anti-rheumatic drugs (DMARDs) and biologics affect various immune responses.
    • B-cell depleting monoclonal antibodies (mAbs) reduce circulating B cells, reducing B-cell-dependent autoimmunity.

    Types of Anti-Drug Antibodies (ADA)

    • ADA can be categorized as Binding or Neutralizing.
    • Binding ADAs interact with the drug molecule but don't inhibit its effect on the target.
    • Neutralizing ADAs directly block drug-target interaction.

    Role of Dendritic Cells

    • DCs capture antigens and enter lymphatic vessels, sampling blood antigens in the spleen.
    • DCs use receptors (like C-type lectins) for direct capture of microbes or proteins.
    • DCs also use pinocytosis to internalize molecules in surrounding fluids.
    • Activation of DCs occurs with cytokines (like TNF) resulting in loss of cell adhesiveness, and expression of receptors for chemokines CCL-19, CCL-21 that drive migration to lymph nodes (lymphatic vessels).

    Overview of Immunoglobulins

    • Immunoglobulins (Ig) are classified into different isotypes: e.g. IgA, IgD, IgE, IgG, and IgM.
    • Each type of Ig has specific functions in the immune response, for example IgA in mucosal immunity, IgE in allergic reactions, IgG in opsonization and complement activation.
    • Antibody isotypes have associated effector functions; for instance, neutralization of microbes, phagocytosis, and complement activation.

    Complement Activation Regulatory Mechanisms

    • Complement activation needs to be regulated because spontaneous low-level activation can harm normal cells and tissues.
    • Different regulatory mechanisms include inhibition of C3 convertase and C5 convertase formation, and inhibition of the membrane attack complex (MAC) formation.

    Role of Infections in Autoimmunity

    • Infections can trigger autoimmunity through molecular mimicry, where microbial antigens resemble self-antigens.
    • Infectious agents can alter antigen presentation.

    Lymphocyte Development

    • Lymphocyte maturation involves sequential stages leading to immunocompetent cells.
    • Stem cell maturation to lymphocytes occurs in generative organs.
    • Lymphocytes are regulated by signals during this development.

    Cytokines

    • Cytokines are crucial in cell signaling for innate and adaptive immunity responses.
    • Cytokines secreted by helper T cells stimulate further T cell proliferation and differentiation.
    • Cytokines also activate other immune cells like B-cells, macrophages, and other leukocytes.

    Immune Synapse

    • The immune synapse is the site of close contact for antigen-specific T cells with antigen-presenting cells (APCs).
    • It is a critical location for T cell activation and signaling.
    • Key functions of the synapse include antigen recognition, signal transduction (stimulating cells), adhesion, and cytokine secretion.

    Mechanisms of CTL-mediated Killing of Target Cells

    • Cytotoxic T cells (CTLs) are specialized lymphocytes responsible for killing infected cells.
    • Perforin/granzyme pathway induces apoptosis in target cells.
    • Fas/FasL pathway also triggers target cells apoptosis.

    Therapeutic Approaches to Immunologic Diseases

    • Immunosuppressive drugs affect immune responses at various levels, including inflammation, T-cell signaling, B-cell activity, and cytokine generation.
    • Numerous strategies target cytokines and their receptors, or processes like costimulation, to dampen immune responses, often in the context of autoimmune diseases.

    Disease Modifying Agents (DMARDs)

    • DMARDs are drugs used to slow the progression of autoimmune diseases (like rheumatoid arthritis).
    • Synthetic DMARDs (e.g. methotrexate, sulfasalazine) usually affect numerous sites within the immune system
    • Biological DMARDs (e.g. anti-TNF mAbs) usually target particular immune players (e.g. cytokines).

    Hypersensitivity Disorders

    • Hypersensitivity is an excessive or inappropriate immune response against harmless substances.
    • Types of hypersensitivity reactions commonly involve antibody-mediated (Type II) and T-cell-mediated (Type IV) responses.

    Autoimmune Disorders

    • Autoimmune disorders are characterized by the loss of self-tolerance, leading to the immune system attacking the body's own tissues.
    • There are over 80 different known forms of autoimmune disease.
    • Some of the most common mechanisms underlying a wide range of organ systems involve cellular and humoral components of the immune system.

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    Immune System and Immunology Final Exam Review PDF

    Description

    This quiz explores the intricate details of primary and secondary immune responses, including the roles of antigen presenting cells and memory lymphocytes. Discover the mechanisms behind T cell activation, the function of co-stimulators, and the impact of cytokines on immune differentiation. Test your knowledge on these crucial topics in immunology.

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