Antigens and Epitopes Quiz
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Questions and Answers

What primarily enhances the immunogenicity of an antigen?

  • Diminished foreignness
  • Increased toxin levels
  • Lipid encapsulation
  • Adjuvant usage (correct)

    • What is a common characteristic of T-independent antigens?

  • Can directly stimulate B-cells (correct)
  • Affect only IgG production
  • Induce antibody class switching
  • Require T-cell participation for response

    • Which of the following factors does NOT affect the immunogenicity of an antigen?

  • Time of day when administered (correct)
  • Molecular weight of the antigen
  • Chemical complexity of the antigen
  • Genetic predisposition of the host

    • What is a primary feature of super antigens (SAgs)?

    <p>Non-specific T-cell activation</p> Signup and view all the answers

    What defines the role of complete Freund's adjuvant in immunology?

    <p>It enhances the persistence of antigens.</p> Signup and view all the answers

    Which type of antigen is specifically involved in class switching during the immune response?

    <p>T-dependent antigens</p> Signup and view all the answers

    Which form of administration is associated with producing unresponsiveness to an antigen?

    <p>High dose administration</p> Signup and view all the answers

    Which of these antigens is associated with human tissue?

    <p>Endogenous antigens</p> Signup and view all the answers

    Which type of antigen is considered to originate from the same species but is not identical to the host's antigens?

    <p>Alloantigens</p> Signup and view all the answers

    What is NOT one of the main functions of macrophages?

    <p>Cellular adhesion</p> Signup and view all the answers

    Which type of cells migrate to local lymph nodes to present antigens to helper T cells?

    <p>Dendritic cells</p> Signup and view all the answers

    Which of the following is a type of macrophage found in the liver?

    <p>Kupffer cells</p> Signup and view all the answers

    Which characteristics are associated with antigen-presenting cells?

    <p>Presence of B7 family molecules</p> Signup and view all the answers

    Which of the following cell types is primarily responsible for the ingestion of particulate matter?

    <p>Granulocytes</p> Signup and view all the answers

    What is the primary function of Langerhans cells?

    <p>Antigen presentation in the skin</p> Signup and view all the answers

    Which statement about heterophile antigens is TRUE?

    <p>They can cross-react with antibodies from unrelated species.</p> Signup and view all the answers

    What distinguishes a hapten from an immunogen?

    <p>Immunogens can induce detectable immune responses.</p> Signup and view all the answers

    What is the role of epitopes in the immune response?

    <p>They bind to specific antibodies or T cell receptors.</p> Signup and view all the answers

    Which of the following statements is true about monoclonal antibodies?

    <p>They interact with a specific epitope on an antigen.</p> Signup and view all the answers

    Which characteristic is NOT associated with antigens?

    <p>They have low immunogenicity.</p> Signup and view all the answers

    What defines the paratope of an antibody?

    <p>It is the antigen-binding site on the antibody.</p> Signup and view all the answers

    What is the significance of immunoreactivity in antigens?

    <p>It represents the ability of an antigen to combine with antibodies or T lymphocytes.</p> Signup and view all the answers

    Which of the following is true regarding antigenic cross-reaction?

    <p>It shows that different antigens can have identical epitopes.</p> Signup and view all the answers

    Which of the following statements correctly describes the types of antigens?

    <p>Antigens may be either soluble or attached to cells or particles.</p> Signup and view all the answers

    Adjuvants primarily enhance the immunogenicity of lipids over proteins.

    <p>False</p> Signup and view all the answers

    T-independent antigens can induce a humoral immune response without the participation of T-cells.

    <p>True</p> Signup and view all the answers

    The chemical complexity and molecular weight of an antigen do not influence its immunogenicity.

    <p>False</p> Signup and view all the answers

    Super antigens cause specific activation of T-cells, targeting particular pathogens.

    <p>False</p> Signup and view all the answers

    Host factors such as age and hormonal balance can affect the immunogenicity of antigens.

    <p>True</p> Signup and view all the answers

    Incomplete Freund's adjuvant is known to be a potent T-cell mitogen.

    <p>False</p> Signup and view all the answers

    Endogenous antigens originate from the body and include blood group antigens.

    <p>True</p> Signup and view all the answers

    Lipid molecules are the primary components of T-dependent antigens.

    <p>False</p> Signup and view all the answers

    Macrophage-like cells are exclusively found in the lungs.

    <p>False</p> Signup and view all the answers

    Heterophile antigens are structurally different in unrelated species.

    <p>False</p> Signup and view all the answers

    All types of dendritic cells are primarily located in the bloodstream.

    <p>False</p> Signup and view all the answers

    Antigen-presenting cells always express low levels of class II MHC molecules.

    <p>False</p> Signup and view all the answers

    Phagocytosis is one of the main functions performed by macrophages.

    <p>True</p> Signup and view all the answers

    Alloantigens are identical to the host's antigens.

    <p>False</p> Signup and view all the answers

    Dendritic cells are less efficient at making contacts with foreign materials compared to other immune cells.

    <p>False</p> Signup and view all the answers

    The monocyte is considered a leukocyte only when it is fixed in a tissue.

    <p>True</p> Signup and view all the answers

    Antigens can only be derived from foreign substances and cannot be self molecules.

    <p>False</p> Signup and view all the answers

    Immunogens are always large molecules that can induce a detectable immune response.

    <p>True</p> Signup and view all the answers

    A hapten can independently induce an immune response without the need for a carrier molecule.

    <p>False</p> Signup and view all the answers

    Each epitope on an antigen is recognized by multiple antibodies due to their similar structure.

    <p>False</p> Signup and view all the answers

    The paratope is the part of the antigen that binds to antibodies.

    <p>False</p> Signup and view all the answers

    Monoclonal antibodies originate from a single clone of plasma B cells and target different epitopes on the same antigen.

    <p>False</p> Signup and view all the answers

    Antigens typically exhibit immunogenicity and immunoreactivity, both essential for effective immune responses.

    <p>True</p> Signup and view all the answers

    Idiotypes refer to the specific antigen determinants found on the epitope of antigens.

    <p>False</p> Signup and view all the answers

    What distinguishes an immunogen from a hapten?

    <p>An immunogen can induce a detectable immune response and usually has high molecular weight, while a hapten cannot induce a response independently and typically has low molecular weight.</p> Signup and view all the answers

    How does the presence of multiple epitopes on an antigen influence the immune response?

    <p>The presence of multiple epitopes allows for a polyclonal immune response, as different antibodies can recognize and bind to various epitopes on the same antigen.</p> Signup and view all the answers

    Explain the significance of paratope in the antibody-antigen interaction.

    <p>The paratope is the specific region of the antibody that binds to the epitope of the antigen, determining the specificity of the immune response.</p> Signup and view all the answers

    What role do carrier proteins play in the function of haptens?

    <p>Carrier proteins enable haptens to successfully induce an immune response by allowing them to be recognized as complete antigens when conjugated to the carrier.</p> Signup and view all the answers

    What is the difference between monoclonal and polyclonal antibodies?

    <p>Monoclonal antibodies are produced by a single clone of plasma B cells and target a specific epitope, whereas polyclonal antibodies are produced by multiple B cell clones and can recognize different epitopes on the same antigen.</p> Signup and view all the answers

    How does the chemical nature of antigens influence their immunogenicity?

    <p>The chemical nature, such as proteins, polysaccharides, or lipids, affects the ability of the antigen to be recognized and elicit an immune response, with proteins usually being more immunogenic.</p> Signup and view all the answers

    Describe the concept of antigenic cross-reaction.

    <p>Antigenic cross-reaction occurs when an antibody produced against one antigen also binds to a different antigen that has a similar epitope, leading to potential immune confusion.</p> Signup and view all the answers

    What is meant by the term idiotope in immunology?

    <p>Idiotopes refer to the specific antigen determinants present on the paratope of an antibody, providing a unique identification for each antibody's binding site.</p> Signup and view all the answers

    What is the relationship between antigen dose and tolerance in the immune response?

    <p>An antigen has an optimum dose, and if administered in significantly lower or higher doses, it can lead to tolerance or unresponsiveness.</p> Signup and view all the answers

    How do T-dependent antigens differ from T-independent antigens in terms of immune cell involvement?

    <p>T-dependent antigens require T-cells for activation of B-cells, while T-independent antigens can activate B-cells directly without T-cell involvement.</p> Signup and view all the answers

    What role do adjuvants play in relation to macrophages and antigen processing?

    <p>Adjuvants enhance the antigen's presentation ability by improving macrophage function and increasing the local cell count involved in the immune response.</p> Signup and view all the answers

    Why are large polysaccharides considered T-independent antigens?

    <p>Large polysaccharides can directly stimulate B-cells without the need for T-cell help, primarily producing an IgM response.</p> Signup and view all the answers

    Explain the significance of super antigens (SAgs) in the immune response.

    <p>Super antigens non-specifically activate T-cells, resulting in massive cytokine release and potential systemic toxicity without traditional antigen processing.</p> Signup and view all the answers

    What factors contribute to the immunogenicity of an antigen?

    <p>Factors include foreignness, chemical complexity, molecular weight, and host factors such as genetics and age.</p> Signup and view all the answers

    How does the molecular weight of an antigen influence its immunogenicity?

    <p>Larger molecular weight antigens are more likely to be processed and recognized by the immune system compared to smaller ones.</p> Signup and view all the answers

    Differentiate between exogenous and endogenous antigens with examples.

    <p>Exogenous antigens originate from outside the host, such as bacterial and viral antigens, while endogenous antigens come from within, like human tissue or blood group antigens.</p> Signup and view all the answers

    What are alloantigens and how do they differ from autoantigens?

    <p>Alloantigens are antigens from the same species as the host but are not identical to the host, while autoantigens are those that belong to the host.</p> Signup and view all the answers

    Describe the main functions of macrophages in the immune response.

    <p>Macrophages perform phagocytosis, antigen presentation, and cytokine production.</p> Signup and view all the answers

    What characteristics allow dendritic cells to be efficient at antigen presentation?

    <p>Dendritic cells have long, narrow processes resembling neuronal dendrites, which enhance contacts with foreign materials.</p> Signup and view all the answers

    What is the mononuclear phagocytic system, and what cells does it consist of?

    <p>The mononuclear phagocytic system consists of monocytes in the blood and macrophages fixed in tissues.</p> Signup and view all the answers

    Explain how heterophile antigens can cause cross-reactivity between unrelated species.

    <p>Heterophile antigens exist in unrelated species but have similar structures, allowing antibodies formed to one to cross-react with another.</p> Signup and view all the answers

    Identify the types of dendritic cells and their primary locations.

    <p>The types of dendritic cells include Langerhans cells, interstitial dendritic cells, myeloid cells, and lymphoid dendritic cells, primarily located in the skin and mucosa.</p> Signup and view all the answers

    What is the primary role of antigen-presenting cells (APCs) in the immune system?

    <p>APCs present antigens to T cells, facilitating their activation and response to pathogens.</p> Signup and view all the answers

    How do macrophages differ based on their tissue location?

    <p>Macrophages are named based on their tissue location, such as alveolar macrophages in the lungs and Kupffer cells in the liver.</p> Signup and view all the answers

    Antigens can be classified as either soluble in body fluids or attached to other ______.

    <p>particles</p> Signup and view all the answers

    The part of the antigen molecule to which the antibody binds is called an ______.

    <p>epitope</p> Signup and view all the answers

    A molecule that can induce a detectable immune response is referred to as an ______.

    <p>immunogen</p> Signup and view all the answers

    A ______ is a molecule that cannot induce a detectable immune response on its own.

    <p>hapten</p> Signup and view all the answers

    Adjuvants enhance the immunogenicity of an ______.

    <p>antigen</p> Signup and view all the answers

    Monoclonal antibodies are produced by a single clone of ______ cells.

    <p>plasma</p> Signup and view all the answers

    Foreignness indicates that an antigen must be ______ to the recipient host.

    <p>non-self</p> Signup and view all the answers

    The term ______ refers to the combining area of the antibody molecule corresponding to the epitope.

    <p>paratope</p> Signup and view all the answers

    T-dependent antigens require the participation of ______ cells to initiate the immune response.

    <p>T</p> Signup and view all the answers

    Immunogenicity is defined as the ability of an antigen to induce a specific ______ response.

    <p>immune</p> Signup and view all the answers

    Antigens may contain a mosaic of ______, which allows for diversity in immune interactions.

    <p>epitopes</p> Signup and view all the answers

    Lipopolysaccharides of gram-negative bacteria are examples of ______ antigens.

    <p>T-independent</p> Signup and view all the answers

    Factors such as genetic makeup, age, and hormonal balance are considered ______ factors in immunogenicity.

    <p>host</p> Signup and view all the answers

    Super antigens cause non-specific activation of ______ cells.

    <p>T</p> Signup and view all the answers

    Each antigen has an optimum ______ that determines its effectiveness in provoking a response.

    <p>dose</p> Signup and view all the answers

    Exogenous antigens include those derived from ______, viral, and parasitic sources.

    <p>bacterial</p> Signup and view all the answers

    Autoantigens are those that belong to the ______;

    <p>host</p> Signup and view all the answers

    ______ antigens are from other species.

    <p>Hetero</p> Signup and view all the answers

    Dendritic cells are primarily found in the skin and ______.

    <p>mucosa</p> Signup and view all the answers

    The monocyte becomes a ______ when fixed in a tissue.

    <p>macrophage</p> Signup and view all the answers

    Macrophages perform three main functions: phagocytosis, antigen presentation, and ______ production.

    <p>cytokine</p> Signup and view all the answers

    Antigen-presenting cells express high levels of both class II ______ molecules.

    <p>MHC</p> Signup and view all the answers

    Examples of macrophage-like cells include alveolar macrophages in the lung and ______ cells in the liver.

    <p>Kupffer</p> Signup and view all the answers

    Heterophile antigens exist in unrelated species, but their structure is so ______ that antibodies formed to one will cross-react with antigens from a different species.

    <p>similar</p> Signup and view all the answers

    Match the following types of antigens with their definitions:

    <p>Immunogen = A molecule that can induce detectable immune response Hapten = An incomplete antigen that cannot induce response unless linked with a carrier Complete antigen = A molecule that can elicit a full immune response Incomple te antigen = A small molecule that requires conjugation to produce immunity</p> Signup and view all the answers

    Match the following components of immunology with their roles:

    <p>Epitopes = Specific parts of an antigen molecule recognized by antibodies Paratopes = Binding sites on antibodies corresponding to epitopes Idiotypes = Specific antigen determinants found on the paratope Mosaic antigens = Antigens containing different epitopes on a single molecule</p> Signup and view all the answers

    Match the following characteristics to the correct terms:

    <p>Immunogenicity = Ability to induce a specific immune response Immunoreactivity = Ability to bind with antibodies or sensitized T cells Polyclonal response = Diverse antibodies reacting to various epitopes of an antigen Monoclonal antibodies = Homogeneous population of antibodies targeting a single epitope</p> Signup and view all the answers

    Match the following types of molecules with their examples:

    <p>Proteins = Albumin as a carrier for haptens Polysaccharides = Complex carbohydrates that can serve as antigens Lipids = Components of lipoproteins which can trigger immune responses Nucleic acids = DNA or RNA molecules that may act as antigens</p> Signup and view all the answers

    Match the following statements with their implications:

    <p>Each antigen molecule has numerous epitopes = Can lead to a broad immune response Haptens need carriers to provoke a response = Demonstrates the importance of molecular weight Self molecules can provoke autoimmune responses = Indicates potential for misidentification by the immune system Antigenic cross-reaction occurs = Reflects structural similarities between different antigens</p> Signup and view all the answers

    Match the following cell types with their immune response functions:

    <p>B cells = Produce antibodies that target antigens T cells = Participate in cell-mediated immunity Plasma B cells = Secrete large amounts of antibodies Memory T cells = Provide long-term immunity against previously encountered antigens</p> Signup and view all the answers

    Match the following characteristics to their respective antigen types:

    <p>Soluble antigens = Present in body fluids and can easily elicit a response Cell-bound antigens = Associated with cellular surfaces and can provoke immune recognition Incomplete antigens = Require a carrier molecule to stimulate an immune reaction Complete antigens = Can independently induce an immune response through their structure</p> Signup and view all the answers

    Match the following types of immune responses with their corresponding components:

    <p>Humoral immune response = Involves B cells and the production of antibodies Cell-mediated immune response = Involves T cells and does not primarily rely on antibodies Adaptive immune response = Provides specificity and memory after an initial exposure Innate immune response = Acts as the first line of defense and is non-specific</p> Signup and view all the answers

    Match the types of antigens with their characteristics:

    <p>T-dependent Antigens = Require T-cell participation for humoral response T-independent Antigens = Stimulate B-cells directly without T-cell help Exogenous Antigens = Derived from pathogens outside the host Endogenous Antigens = Originated from the host's own tissues</p> Signup and view all the answers

    Match the factors affecting immunogenicity with their descriptions:

    <p>Foreignness = The non-self nature of an antigen Chemical complexity = Degree to which an antigen is composed of varied structures Molecular weight = Size of antigen necessary for processing Dose of antigen = The optimal amount needed to elicit a response</p> Signup and view all the answers

    Match the types of adjuvants with their examples:

    <p>Incomplete Freund's adjuvant = Used to boost immune response without complete antigen Complete Freund's adjuvant = Contains killed mycobacteria to enhance response Alum = Commonly used for vaccines to enhance immunogenicity Saponin = Plant-derived adjuvant to increase immune activation</p> Signup and view all the answers

    Match the types of cells with their functions in the immune response:

    <p>Macrophages = Ingest and process antigens for T-cells B-cells = Produce antibodies in response to antigen recognition T-helper cells = Assist in activating B-cells and other immune cells Dendritic cells = Present antigens to naive T-cells for activation</p> Signup and view all the answers

    Match the components of super antigens (SAgs) with their effects:

    <p>Non-specific T-cell activation = Trigger proliferation of CD4+ T-cells Massive cytokine release = Cause systemic inflammation and toxicity Potent T cell Mitogen = Activate T-cells independently of antigen processing Systemic toxicity = Potentially harmful effects from excessive cytokine levels</p> Signup and view all the answers

    Match the classifications of antigens according to their source:

    <p>Bacterial antigens = Examples include components of bacterial cells Viral antigens = Derived from viruses and can provoke immune response Parasitic antigens = Associated with organisms causing parasitic infections Human tissue antigens = Include antigens present in the body’s own cells</p> Signup and view all the answers

    Match the types of antibody responses with the type of antigens involved:

    <p>IgM response = Triggered by T-independent antigens Class switching = Occurs with T-dependent antigens Memory cell formation = Associated with T-dependent antigens No memory response = Characterizes T-independent antigens</p> Signup and view all the answers

    Match the root of administration with its associated effect on immunogenicity:

    <p>Oral = Generally results in tolerance if doses are too high IV (intravenous) = Provides rapid systemic distribution of antigen IM (intramuscular) = Commonly used for vaccinations and robust response Subcutaneous = Often leads to localized immunogenicity</p> Signup and view all the answers

    Match the following types of antigens with their descriptions:

    <p>Autoantigens = Antigens that belong to the host Alloantigens = Antigens from the same species but not identical to the host Heteroantigens = Antigens originating from other species Heterophile antigens = Similar structure antigens from unrelated species</p> Signup and view all the answers

    Match the following antigen-presenting cells with their characteristics:

    <p>Macrophages = Ingest particulate matter and present antigens B cells = Can act as antigen-presenting cells and produce antibodies Dendritic cells = Efficient at making contacts with foreign materials Monocytes = Leukocytes in transit that become macrophages in tissues</p> Signup and view all the answers

    Match the following functions of macrophages with their correct descriptions:

    <p>Phagocytosis = The ingestion of particles or microorganisms Antigen presentation = Showing antigens to T cells for immune response Cytokine production = Secretion of signaling proteins that regulate immune responses Tissue-specific functions = Named depending on their tissue locations</p> Signup and view all the answers

    Match the following types of dendritic cells with their locations:

    <p>Langerhans cells = Primarily found in the skin Interstitial dendritic cells = Found in tissues between cells Myeloid cells = Derived from bone marrow progenitors Lymphoid dendritic cells = Present in lymphoid tissues and organs</p> Signup and view all the answers

    Match the following secreted substances to their functions:

    <p>Cytokines = Regulate immune system communication and responses Costimulatory factors = Enhance the activation of T cells Antibodies = Bind and neutralize antigens Monokines = Produced by macrophages to trigger immune responses</p> Signup and view all the answers

    Match the following types of macrophage-like cells with their specific names:

    <p>Alveolar macrophages = Found in the lung alveoli Histiocytes = Located in connective tissues Kupffer cells = Macrophages in the liver Microglial cells = Macrophages in the central nervous system</p> Signup and view all the answers

    Match the following immunological concepts with their definitions:

    <p>Antigen-presenting cells = Cells that display foreign antigens to T cells Cross-reactivity = When antibodies react with antigens from different species Phagocytosis = The process of engulfing and digesting pathogens MHC molecules = Proteins that present peptides to T cells</p> Signup and view all the answers

    Match the following descriptions of antigen function with their corresponding terms:

    <p>Immunogenicity = The ability of an antigen to induce an immune response Structural similarity = Basis for cross-reactivity among different antigens Specificity = The unique interaction between an antibody and its epitope Memory response = Long-term immunity due to prior exposure to an antigen</p> Signup and view all the answers

    Study Notes

    Antigens (Ags)

    • Antigens are substances that induce the production of antibodies (antibody generator).
    • Antigens can induce both types of immune response, and bind to products of the immune response.
    • Antigens are molecules recognized by antigen receptors of B or T cells.
    • Antigens are not just components of foreign substances (pathogens). A large variety of self-molecules can serve as Ags as well, provoking autoimmune responses.

    Characteristics of Ags

    • Immunogenicity: The ability of an antigen to induce a specific immune response.
    • Immunoreactivity: The ability of an antigen to combine with corresponding Ab or sensitized T lymphocytes.
    • Antigens can be either soluble in body fluids or attached to other particles (cells).
    • Antigens can be proteins, polysaccharides, lipids, nucleic acids, complexes (lipoprotein, lipopolysaccharide), or small inorganic chemicals.

    Epitopes (Antigenic Determinants)

    • Each antigen molecule has a set of epitopes.
    • Epitopes are the parts of an antigen molecule that antibodies (or T cell receptors) bind to.
    • Antigens usually have many determinants.
    • Each epitope is recognized by a single antibody based on its unique molecular shape.
    • Each antigen molecule results in a polyclonal immune response.

    Monoclonal Antibodies

    • A homogeneous antibodies population that interacts with a particular epitope on the antigen.
    • Usually produced by the same clone of plasma B cells.

    Paratope

    • The combining area of the antibody molecule, corresponding to the epitope.
    • Epitope and paratope determine specificity, which is a hallmark of immunological reactions.
    • Bacteria/viruses may contain an antigen mosaic (different epitopes), while the same epitope on different antigens may present causing antigenic cross-reaction.
    • Specific antigen determinants on paratope are called IDIOTOPES.

    Immunogen and Hapten

    • Immunogen: A molecule that can induce a detectable immune response (complete antigen). Usually has a high molecular weight.
    • Hapten: A molecule that cannot induce a detectable immune response (incomplete antigen). Usually has a low molecular weight.
    • Hapten needs to be conjugated to other molecules called carriers, which are usually proteins (albumin) but can be polysaccharides.
    • Examples of haptens include simple chemicals and drugs (penicillin, aspirin, cosmetics, neomycin skin ointment).

    Adjuvant

    • A substance that enhances the immunogenicity of an antigen.
    • Mechanisms of adjuvants:
      • Change the chemical and physical characteristics of the Ag.
      • Improve the Ag processing and presentation ability of macrophages.
      • Stimulate proliferation of lymphocytes.
    • Most adjuvants work by keeping the antigen in the area and increasing the number of cells involved in the immune response.
    • Common adjuvants include Incomplete Freund’s adjuvant and Complete Freund’s adjuvant.

    Factors Affecting Immunogenicity

    • Foreignness: Ag must be foreign (non-self) to the recipient host to induce an immune response.
    • Chemical complexity: e.g. Proteins are more antigenic than lipids.
    • Molecular weight: The antigen must be large enough to be processed.
    • Host factors: Genetic, age, gender, hormonal balance... etc.
    • Dose of antigen: Each antigen has an optimum dose. If the dose is significantly lower or higher than the optimum, this results in tolerance (unresponsiveness to antigen).
    • Route of administration: Oral, IV, IM, Subcutaneous.

    Types of Antigens

    • According to their recognition by B-cells:
      • T-dependent antigens: Require participation of T cells (TH-2) to induce a humoral immune response. Mostly are proteins. Result in antibody class switching in secondary Ab response. There are B &T memory cells. Example: Most pathogens.
      • T-independent antigens: Don't require participation of T cells to induce a humoral immune response. They have the ability to directly stimulate the B cell. Mostly are large polysaccharide and lipid molecules. Produce only IgM antibody response. No class-switching or memory cells. Examples: Lipopolysaccharides of gram-negative bacteria and bacterial nucleic acid.
    • According to the source of antigens:
      • Exogenous antigens: Bacterial, Viral, Parasitic antigens.
      • Endogenous antigens: Human tissue antigens, blood group antigens (A, B, and Rh antigens), Major Histocompatibility Complex antigens (MHC).

    Super Antigens (SAgs)

    • A class of antigens that cause nonspecific activation of T cells.
    • They are potent T cell mitogens, triggering mitosis of CD4+ cells in the absence of Ag processing.
    • They result in polyclonal T cell activation and massive cytokine release.
    • The massive T-cell activation and release of large amounts of cytokines cause systemic toxicity.
    • This method of stimulation is not specific for the pathogen, meaning it doesn’t lead to acquired immunity (i.e. no memory).
    • Examples: bacterial toxins as SAgs (e.g. Toxic Shock Syndrome Toxin (TSST)).

    Relationship of Antigens to the Host

    • Autoantigens: Belong to the host.
    • Alloantigens: From the same species as the host but are not identical to the host.
    • Heteroantigens: From other species.
    • Heterophile Antigens: Exist in unrelated species, but their structure is so similar that antibody formed to one will cross-react with antigen from a different species.

    Antigen-Presenting Cells

    • These are a heterogeneous population of leukocytes.
    • Primarily found in the skin, lymph nodes, thymus, and within mucosal epithelia.
    • Types:
      • Macrophages
      • B cells
      • Dendritic cells

    Macrophages

    • The mononuclear phagocytic system consists of monocytes circulating in the blood and macrophages in the tissues.
    • Monocytes are leukocytes in transit through the blood, which become macrophages when fixed in a tissue.
    • Monocytes, macrophages, and granulocytes can ingest particulate matter (microorganisms, cells, inert particles) and therefore have phagocytic functions.
    • Macrophage-like cells serve different functions in different tissues and are named according to their tissue location.

    Functions of Macrophages

    • Phagocytosis
    • Antigen presentation
    • Cytokine production

    Dendritic Cells

    • Named for their many long, narrow processes that resemble neuronal dendrites, which make them very efficient at making contacts with foreign materials.
    • Primarily present in the skin (e.g., Langerhans cells) and the mucosa, from where they migrate to local lymph nodes for presentation of antigens to helper T cells.

    Types of Dendritic Cells

    • Langerhans cells
    • Interstitial dendritic cells
    • Myeloid cells
    • Lymphoid dendritic cells

    Antigen Presenting Cells

    • All antigen-presenting cells constitutively express high levels of both class II MHC molecules and members of the costimulatory B7 family.

    Antigens

    • Substances that induce the production of antibodies and bind to products of immune responses.
    • They can be components of foreign substances (pathogens) or self-molecules, provoking autoimmune responses.
    • Two main characteristics:
      • Immunogenicity: the ability to stimulate an immune response
      • Immunoreactivity: the ability to bind to antibodies or sensitized T lymphocytes
    • Can be soluble in body fluids or attached to other particles (cells).
    • Chemically, antigens can be proteins, polysaccharides, lipids, nucleic acids, or complex combinations.

    Epitope (Antigenic Determinants)

    • The specific part of an antigen that binds to an antibody or T cell receptor.
    • Each antigen molecule has multiple epitopes.
    • Each epitope is recognized by a single antibody, based on the different molecular shapes.
    • Each antigen molecule elicits a polyclonal immune response, involving multiple antibodies.

    Paratope

    • The combining region of an antibody molecule that corresponds to the epitope.
    • The epitope and paratope interaction determine specificity in immunological reactions.
    • Specific antigen determinants on the paratope are called Idiotopes.

    Immunogen vs. Hapten

    • Immunogen: A molecule that induces a detectable immune response (complete antigen). Usually has a high molecular weight.
    • Hapten: A molecule that cannot induce a detectable immune response on its own (incomplete antigen). Usually has a low molecular weight. Requires conjugation to a carrier molecule, such as a protein or polysaccharide, to become immunogenic.
      • Examples: Simple chemicals and drugs like penicillin, aspirin, cosmetics, and neomycin skin ointment.

    Adjuvant

    • A substance that enhances the immunogenicity of an antigen.
    • Mechanisms:
      • Modifies the chemical and physical characteristics of the antigen.
      • Improves antigen processing and presentation by macrophages.
      • Stimulates lymphocyte proliferation.
    • Common adjuvants: Incomplete Freund’s adjuvant and Complete Freund’s adjuvant.

    Factors Affecting Immunogenicity

    • Foreignness: The antigen must be foreign (non-self) to the recipient host.
    • Chemical complexity: Proteins are more antigenic than lipids.
    • Molecular weight: The antigen must be large enough to be processed by the immune system.
    • Host factors: Genetics, age, gender, hormonal balance.
    • Dose of antigen: There is an optimal dose for each antigen, with lower or higher doses leading to tolerance.
    • Route of administration: Oral, intravenous, intramuscular, subcutaneous.

    Types of Antigens Based on Recognition by B-cells

    • T-dependent Antigens: Require participation of T cells (TH-2) to induce humoral immune responses. Mostly proteins. Result in antibody class switching in secondary responses. Create B and T memory cells. Examples: Most pathogens.
    • T-independent Antigens: Do not require participation of T cells. Can directly stimulate B cells. Mostly large polysaccharides and lipid molecules. Produce only IgM antibody responses. No class switching or memory cells. Examples: Lipopolysaccharides of gram-negative bacteria and bacterial nucleic acids.

    Types of Antigens Based on Source

    • Exogenous Antigens: Antigens from external sources
      • Bacterial antigens
      • Viral antigens
      • Parasitic antigens
    • Endogenous Antigens: Antigens produced by the host’s own cells
      • Human tissue antigens
      • Blood group antigens (A, B, and Rh antigens)
      • Major histocompatibility complex (MHC) antigens

    Superantigens (SAgs)

    • A class of antigens that cause non-specific activation of T cells, leading to polyclonal T cell activation and massive cytokine release.
    • They trigger mitosis of CD4+ T cells in the absence of antigen processing.
    • This non-specific stimulation causes systemic toxicity and does not lead to acquired immunity (no memory cells).
    • Examples: Bacterial toxins like Toxic Shock Syndrome Toxin (TSST).

    Relationship of Antigens to the Host

    • Autoantigens: Antigens that belong to the host.
    • Alloantigens: Antigens from the same species but are not identical to the host.
    • Heteroantigens: Antigens from other species.
    • Heterophile Antigens: Antigens found in unrelated species but have similar structures, leading to cross-reactivity.

    Antigen-Presenting Cells (APCs)

    • Heterogeneous population of leukocytes found in the skin, lymph nodes, thymus, and mucosal epithelia.
      • Macrophages: Part of the mononuclear phagocytic system, consisting of monocytes in blood and macrophages in tissues. Monocytes become macrophages when they reside in a tissue. Phagocytic cells that ingest particulate matter. Macrophages serve different functions in different tissues, e.g., alveolar macrophages, histiocytes, Kupffer cells, mesangial cells, microglial cells, and osteoclasts.
      • B Cells: Can act as APCs.
      • Dendritic Cells: Characterized by long, narrow processes resembling neuronal dendrites. Primarily present in the skin (Langerhans cells) and mucosa, migrating to lymph nodes to present antigens to helper T cells. Four types: Langerhans cells, interstitial dendritic cells, myeloid cells, and lymphoid dendritic cells.

    Functions of Macrophages

    • Phagocytosis
    • Antigen presentation
    • Cytokine production

    Common Characteristics of APCs

    • APCs constitutively express high levels of both class II MHC molecules and members of the B7 costimulatory family.

    Antigens

    • Antigens (Ags) can trigger the production of antibodies and immune responses.
    • Antigens are recognized by B or T cell antigen receptors.
    • Antigens can be components of foreign substances or self molecules that provoke autoimmune responses.

    Characteristics of Antigens

    • Immunogenicity: The ability of an antigen to induce a specific immune response.
    • Immunoreactivity: The ability of an antigen to bind with antibodies or sensitized T lymphocytes.
    • Antigens can be soluble in body fluids, attached to particles (cells), or consist of proteins, polysaccharides, lipids, nucleic acids, or other small inorganic chemicals.
    • Each antigen has epitopes (antigenic determinants), the part of the antigen molecule that antibodies or T cell receptors bind to.
    • Multiple epitopes on a single antigen can be recognized by different antibodies, resulting in a polyclonal immune response.
    • Monoclonal antibodies are a homogenous population of antibodies that interact with a specific epitope on the antigen.

    Paratope

    • The paratope is the combining area of the antibody molecule that corresponds to the epitope.
    • Epitopes and paratopes determine the specificity of immunological reactions.
    • Bacterial or viral antigens can have multiple epitopes, and the same epitope can exist on different antigens, causing antigenic cross-reaction.
    • Specific antigenic determinants on the paratope are called idiotopes.

    Immunogen & Hapten

    • Immunogen: A molecule that induces a detectable immune response (complete antigen). It usually has a high molecular weight.
    • Hapten: A molecule that cannot induce a detectable immune response (incomplete antigen). It usually has a low molecular weight.
    • Haptens require conjugation to carrier molecules, usually proteins, to become immunogenic.
    • Examples of haptens include penicillin, aspirin, cosmetics, and neomycin skin ointment.

    Adjuvant

    • Adjuvants enhance the immunogenicity of an antigen by changing the chemical and physical characteristics of the antigen.
    • Adjuvants improve the antigen processing and presentation ability of macrophages, stimulate lymphocyte proliferation, and keep the antigen in the area, increasing immune response cells.
    • Common examples of adjuvants are incomplete Freund's adjuvant and complete Freund's adjuvant.

    Factors Affecting Immunogenicity

    • Foreignness: Antigens must be foreign (non-self) to the recipient host to induce an immune response.
    • Chemical complexity: Proteins are more antigenic than lipids.
    • Molecular Weight: The antigen must be large enough to be processed.
    • Host factors: Genetic makeup, age, gender, hormonal balance, etc.
    • Dose of antigen: Each antigen has an optimal dose. Lower or higher doses can lead to tolerance (unresponsiveness to the antigen).
    • Route of administration: Oral, intravenous, intramuscular, subcutaneous.

    Types of Antigens

    • T-dependent Antigens: Require the participation of T helper cells (TH-2) to induce humoral immune response. They are mostly proteins and result in antibody class switching in secondary antibody response.
    • T-independent Antigens: Don't require T cell participation to induce humoral immune response. They directly stimulate B cells and are often large polysaccharide and lipid molecules. They primarily produce IgM antibody response and don’t have class-switching or memory cells.
    • Exogenous Antigens: Derived from outside the body. Examples include bacterial, viral, and parasitic antigens.
    • Endogenous Antigens: Derived from within the body. Examples include human tissue antigens, blood group antigens (A, B, Rh), and Major Histocompatibility Complex antigens (MHC).

    Super Antigens (SAg)

    • Super antigens are a class of antigens that cause non-specific activation of T cells, leading to polyclonal T cell activation and massive cytokine release.
    • Super antigens activate T cells independently of antigen processing.
    • The massive T cell activation and cytokine release cause systemic toxicity.
    • This method of stimulation is not specific for the pathogen and doesn't lead to acquired immunity or memory.
    • Examples of bacterial superantigens include Toxic Shock Syndrome Toxin (TSST).

    Relationship of Antigens to the Host

    • Autoantigens: Antigens that belong to the host.
    • Alloantigens: Antigens from the same species as the host but are not identical.
    • Heteroantigens: Antigens from other species.
    • Heterophile antigens: Antigens that exist in unrelated species but have similar structures, causing cross-reactivity.

    Antigen-Presenting Cells

    • Antigen-presenting cells are a heterogeneous population of leukocytes that are primarily found in the skin, lymph nodes, thymus, and mucosal epithelia.
    • They are responsible for presenting processed antigens to T cells.
    • Major types of antigen-presenting cells include:
      • Macrophages: Phagocytic cells that engulf foreign materials and present antigens to T cells.
      • B cells: Lymphocytes that can both recognize and present antigens to T cells.
      • Dendritic cells: Highly specialized cells that are highly efficient at capturing and presenting antigens to T cells.

    Macrophages

    • Macrophages are derived from monocytes and are found in various tissues throughout the body.
    • They perform phagocytosis, antigen presentation, and cytokine production.

    Dendritic Cells

    • Dendritic cells have many long, narrow processes that resemble neuronal dendrites, allowing them to efficiently capture and present antigens to T cells.
    • They are mainly present in the skin (e.g., Langerhans cells) and mucosa.
    • Dendritic cells migrate to local lymph nodes to present antigens to helper T cells.
    • Types of dendritic cells include Langerhans cells, interstitial dendritic cells, myeloid dendritic cells, and lymphoid dendritic cells.

    Antigen Presenting Cells

    • All antigen-presenting cells express high levels of class II MHC molecules and costimulatory B7 molecules, which are important for activating T cells.

    Antigens (Ags)

    • Antigens are substances that induce the production of antibodies.
    • Antigens can induce both types of immune responses and bind to products of immune response.
    • Antigens are not just components of foreign substances.
    • A large variety of self molecules can serve as antigens as well, provoking autoimmune responses.

    Characteristics of Ag

    • Immunogenicity: The ability of an antigen to induce a specific immune response.
    • Immunoreactivity: The ability of an antigen to combine with corresponding antibodies or sensitized T lymphocytes.
    • Chemical Nature: Antigens can be proteins, polysaccharides, lipids, nucleic acids, complex combinations (lipoprotein, lipopolysaccharide), or small inorganic chemicals.
    • Epitopes: Each antigen molecule has a set of epitopes (antigenic determinants), which are the specific parts of an antigen molecule that antibodies or T cell receptors bind to.

    Epitope and Paratope

    • Paratope: The combining area of the antibody molecule, corresponding to the epitope.
    • Specificity: Epitopes and paratopes determine specificity, which is a hallmark of immunological reactions.
    • Antigen Mosaic: Bacteria or viruses may contain an antigen mosaic (different epitopes).
    • Antigenic Cross-Reaction: The same epitope on different antigens may present, causing an antigenic cross-reaction.
    • Idiotopes: Specific antigen determinants on paratopes are called idiotopes.

    Immunogen and Hapten

    • Immunogen: A molecule that can induce a detectable immune response (complete antigen). Usually, immunogens have a high molecular weight.
    • Hapten: A molecule that cannot induce a detectable immune response (incomplete antigen). Usually haptens have a low molecular weight.
    • Carrier: Haptens need to be conjugated to other molecules called carriers, which are usually proteins (albumin) but can be polysaccharides.
    • Examples of Haptens: Simple chemicals and drugs like penicillin, aspirin, cosmetics, and neomycin skin ointment.

    Adjuvant

    • Adjuvant: A substance that enhances the immunogenicity of an antigen.
    • Mechanisms of Adjuvants:
      • Change the chemical and physical characteristics of the antigen.
      • Improve the antigen processing and presentation ability of macrophages.
      • Stimulate proliferation of lymphocytes.
      • Keep the antigen in the area and increase the number of cells involved in the immune response.
    • Common Adjuvants: Incomplete Freund's adjuvant and Complete Freund's adjuvant.

    Factors Affecting Immunogenicity

    • Foreignness: An antigen must be foreign (non-self) to the recipient host to induce an immune response.
    • Chemical Complexity: Proteins are more antigenic than lipids.
    • Molecular Weight: The antigen must be large enough to be processed.
    • Host Factors: Genetic factors, age, gender, hormonal balance, etc.
    • Dose of Antigen: Each antigen has an optimum dose. Lower or higher doses can lead to tolerance (unresponsiveness to the antigen).
    • Route of Administration: Oral, intravenous, intramuscular, subcutaneous.

    Types of Antigens

    • B-Cell Recognition:

      • T-dependent antigens: Require the participation of T-cells (TH-2) to induce a humoral immune response. Mostly proteins. Result in antibody class switching in the secondary antibody response. Have B and T memory cells. Examples include most pathogens.
      • T-independent antigens: Don't require the participation of T-cells to induce a humoral immune response. Can directly stimulate B-cells. Mostly large polysaccharide and lipid molecules. Produce only IgM antibody response. No class-switching and no memory cells. Examples include lipopolysaccharides of gram-negative bacteria and bacterial nucleic acid.

    • Source of Antigens:

      • Exogenous antigens:
        • Bacterial antigens
        • Viral antigens
        • Parasitic antigens
      • Endogenous antigens:
        • Human tissue antigens
        • Blood group antigens (A, B, and Rh antigens)
        • Major histocompatibility complex antigens (MHC)

    Superantigens (SAgs)

    • Superantigens: A class of antigens that cause non-specific activation of T-cells (potent T-cell mitogen trigger mitosis of CD4+ cells in the absence of antigen processing). Result in polyclonal T-cell activation and massive cytokine release.
    • Systemic Toxicity: Massive T-cell activation and release of large amounts of cytokines cause systemic toxicity.
    • Non-Specific Stimulation: Superantigens do not lead to acquired immunity (no memory).
    • Examples of Bacterial Toxins as SAgs: Toxic Shock Syndrome Toxin (TSST).

    Relationship of Antigens to the Host

    • Autoantigens: Belong to the host.
    • Alloantigens: From the same species as the host but not identical to the host.
    • Heteroantigens: From other species.
    • Heterophile Antigens: Exist in unrelated species, but their structure is so similar that antibody formed to one will cross-react with antigen from a different species.

    Antigen-Presenting Cells

    • Antigen-presenting cells: Heterogeneous population of leukocytes found primarily in the skin, lymph nodes, thymus, and within mucosal epithelia.
    • Types of Antigen-Presenting Cells:
      • Macrophages
      • B cells
      • Dendritic cells

    Macrophages

    • Mononuclear Phagocytic System: Consists of monocytes circulating in the blood and macrophages in the tissues. Monocytes are leukocytes in transit through the blood that become macrophages when fixed in a tissue.
    • Phagocytosis: Monocytes, macrophages, and granulocytes can ingest particulate matter (microorganisms, cells, inert particles) and are therefore phagocytic.
    • Tissue-Specific Macrophages: Macrophage-like cells serve different functions in different tissues and are named according to their location. Examples include: alveolar macrophages in the lung, histiocytes in connective tissues, Kupffer cells in the liver, mesangial cells in the kidney, microglial cells in the brain, and osteoclasts in the bone.

    Functions of Macrophages

    • Phagocytosis: Ingesting and destroying foreign particles.
    • Antigen Presentation: Displaying processed antigens to T-cells.
    • Cytokine Production: Secreting signaling molecules that regulate the immune response.

    Dendritic Cells

    • Morphology: Have many long, narrow processes resembling neuronal dendrites, making them efficient at making contacts with foreign materials.
    • Location and Function: Primarily present in the skin (Langerhans cells) and the mucosa. They migrate to local lymph nodes for presentation of antigen to helper T-cells.

    Types of Dendritic Cells

    • Langerhans cells: Found in the skin.
    • Interstitial dendritic cells: Found in tissues.
    • Myeloid dendritic cells: Derived from bone marrow.
    • Lymphoid dendritic cells: Derived from lymphoid tissues.

    Antigen Presenting Cells

    • MHC and Costimulatory Molecules: All antigen-presenting cells constitutively express high levels of both class II MHC molecules and members of the costimulatory B7 family.

    Antigens

    • Substances that induce the production of antibodies (antibody generators).
    • Can induce both types of immune responses and bind to products of immune response.
    • Not limited to foreign substances (pathogens), self-molecules can also serve as antigens, provoking autoimmune responses.

    Characteristics of Antigens

    • Immunogenicity: Ability to induce a specific immune response.
    • Immunoreactivity: Ability to combine with corresponding antibody or sensitized T lymphocytes.
    • Can be soluble in body fluids or attached to other particles (cells).
    • Chemical nature can be proteins, polysaccharides, lipids, nucleic acids, complexes (lipoprotein, lipopolysaccharide) or other small inorganic chemicals.
    • Each antigen molecule has a set of epitopes (antigenic determinants), the specific part of the antigen molecule that the antibody or T cell receptor binds to.
    • Most antigens have multiple epitopes.
    • Each epitope is recognized by a single antibody.
    • Each antigen molecule results in a polyclonal immune response.
    • A homogenous population of antibodies interacting with a particular epitope is called a monoclonal antibody.

    Paratope

    • Combining area of the antibody molecule, corresponding to the epitope.
    • Determines specificity in immune reactions along with the epitope.
    • Bacteria/viruses may contain antigen mosaics (different epitopes) and the same epitope can exist on different antigens, causing antigenic cross-reactions.
    • Specific antigenic determinants on paratope are called IDIOTOPES.

    Immunogen and Hapten

    • Immunogen is a molecule that can induce a detectable immune response (complete antigen). Usually has a high molecular weight.
    • Hapten is a molecule that cannot induce a detectable immune response (incomplete antigen), usually has a low molecular weight.
    • Haptens need to be conjugated to other molecules called carriers, usually proteins (albumin) but can be polysaccharides.
    • Examples of haptens: simple chemicals and drugs such as penicillin, aspirin, cosmetics, neomycin skin ointment.

    Adjuvant

    • A substance that enhances the immunogenicity of an antigen.
    • Mechanisms of adjuvant:
      • Change the chemical and physical characteristics of the antigen.
      • Improve antigen processing and presentation by macrophages.
      • Stimulate the proliferation of lymphocytes.
    • Most adjuvants work by keeping the antigen in the area and increasing the number of cells involved in the immune response.
    • Common adjuvants:
      • Incomplete Freund’s adjuvant.
      • Complete Freund’s adjuvant.

    Factors Affecting Immunogenicity

    • Foreignness: Antigen must be foreign (non-self) to induce an immune response.
    • Chemical complexity: Proteins are more antigenic than lipids.
    • Molecular Weight: Must be large enough to be processed.
    • Host factors: Genetic, age, gender, hormonal balance etc.
    • Dose of antigen: Each antigen has an optimum dose, resulting in tolerance if the dose is significantly lower or higher.
    • Route of administration: Oral, intravenous, intramuscular, subcutaneous.

    Types of Antigens

    • According to recognition by B-cells:

      • T-dependent antigens: Require the participation of T-cells (TH-2) to induce a humoral immune response. Mostly proteins. Result in antibody class switching in secondary antibody responses. There are B and T memory cells, eg. pathogens.
      • T-independent antigens: Do not require T-cell participation, directly stimulate B-cells. Mostly large polysaccharide and lipid molecules, only produce IgM antibody responses. No class switching, no memory cells, eg. lipopolysaccharides of gram-negative bacteria and bacterial nucleic acid.

    • According to the source of antigens:

      • Exogenous antigens: From outside the body, eg. bacterial, viral, parasitic antigens.
      • Endogenous antigens: From inside the body, eg. human tissue antigens, blood group antigens (A, B, and Rh), major histocompatibility complex (MHC) antigens.

    Super antigens (SAgs)

    • Class of antigens that cause non-specific activation of T-cells (potent T cell mitogen), resulting in polyclonal T cell activation and massive cytokine release.
    • This non-specific stimulation does not lead to acquired immunity and there is no memory.
    • The massive T-cell activation and release of large amounts of cytokines cause systemic toxicity.
    • Examples of bacterial SAgs: Toxic Shock Syndrome Toxin (TSST).

    Relationship of Antigens to the Host

    • Autoantigens: Belong to the host.
    • Alloantigens: From the same species as the host but are not identical to the host.
    • Heteroantigens: From other species.
    • Heterophile antigens: Exist in unrelated species but have similar structures, antibodies formed against one can cross-react with antigen from a different species.

    Antigen-presenting Cells (APCs)

    • Heterogeneous population of leukocytes found primarily in the skin, lymph nodes, thymus, and mucosal epithelia.
    • Examples of APCs:
      • Macrophages.
      • B cells.
      • Dendritic cells.

    Macrophages

    • Mononuclear phagocytic system: Consists of monocytes circulating in the blood and macrophages in the tissues.
    • Monocytes are leukocytes in transit through the blood that become macrophages when fixed in a tissue.
    • Monocytes, macrophages, and granulocytes can ingest particulate matter and are said to have phagocytic functions.
    • Macrophage-like cells serve different functions in different tissues and are named according to their tissue location, eg. alveolar macrophages, histiocytes, Kupffer cells, mesangial cells, microglial cells, osteoclasts.

    Functions of Macrophages

    • Phagocytosis.
    • Antigen presentation.
    • Cytokine production.

    Dendritic Cells

    • Named for their many long, narrow processes that resemble neuronal dendrites, making them efficient at making contact with foreign materials.
    • Primarily present in the skin (Langerhans cells) and mucosa, migrating to local lymph nodes to present antigen to helper T cells.

    Types of Dendritic Cells

    • Langerhans cells.
    • Interstitial dendritic cells.
    • Myeloid dendritic cells.
    • Lymphoid dendritic cells.

    Antigen-Presenting Cells (APCs)

    • All APCs constitutively express high levels of both class II MHC molecules and members of the costimulatory B7 family.

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    Antigen and Super Antigen PDF

    Description

    Test your knowledge on antigens, their characteristics, and the role of epitopes in immune response. This quiz covers immunogenicity, immunoreactivity, and the types of antigens found in the body. Perfect for students studying immunology or related fields.

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