kul 2. prinsip dasar imunologi

Click here to load reader

Post on 24-Jan-2017

115 views

Category:

Education

16 download

Embed Size (px)

TRANSCRIPT

  • Immunology I: Basic Principles of Adaptive Immunity and Immunization

    Gusti Ayu Rai Saputri,M.Si., Apt..Copyright 2005 by John Wiley & Sons, Inc.

    *

  • Immunology and ImmunityImmunity: refers to the ability of an organism to recognize and defend itself against infectious agents

    Susceptibility: opposite of immunity, is the vulnerability of the host to harm by infectious agents

    Immunology: the study of adaptive immunity and how the immune system responds to specific infectious agents and toxins

    Immune system: consists of various cells, especially lymphocytes, and organs such as the thymus gland, that help provide the host with specific immunity to infectious agents

    *

  • Types of ImmunityInnate immunity (genetic): exists because of genetically determined characteristics

    All humans have immunity to many infectious agents that cause disease in pets and domestic animals

    Adaptive immunity (acquired): immunity obtained in some manner other than heredity

    Naturally acquired adaptive immunity is most often obtained by having a specific diseaseArtificially acquired adaptive immunity is obtained by receiving an antigen by injection of vaccine or immune serum

    *

  • The various types of immunity: nonspecific immunity is largely innate, whereas specific immunity is acquired

    *

  • Characteristics of the Immune SystemAntigen: a substance the body identifies as foreign and toward which it mounts an immune response

    Large, complex proteins can have several epitopes, or antigenic determinants (areas on the molecule to which antibodies can bind)

    Hapten: a small molecule can act as an antigen if it binds to a larger protein molecule

    Antibody: a protein produced in response to an antigen that is capable of binding specifically to the antigen

    Titer: the quantity of a substance needed to produce a given reaction

    *

  • A typical antigen-antibody reaction: antibodies bind to specific chemical groups or structures, called epitopes or antigenic determinants

    *

  • A typical antigen: antibody reaction: gram-negative bacterial pathogen may have several antigens, or immunogens (flagella, pili and cell wall)

    *

  • Cells and Tissues of the Immune SystemSpecific immune responses are carried out by lymphocytes which develop from stem cells as do other white blood cells, red blood cells, and platelets

    B lymphocytes (B cells): lymphocytes are processed and mature in tissue, referred to as bursal-equivalent tissue

    T lymphocytes ( T cells): stem cells migrate to the thymus, where they undergo differentiation into thymus-derived cells

    Natural killer cells (NK): found in tissues and circulating in blood and nonspecifically kill cancer cells and viral-infected cells

    *

  • Differentiation of stem cells into B cells and T cells. This occurs in the bone marrow and thymus.

    *

  • *

  • *

  • The Bursa of Fabricus In chickens this is where B cells develop

    *

  • Dual Nature of the Immune SystemLymphocytes give rise to two major types of immune responses

    Humoral immunity: carried out by antibodies circulating in the blood

    Cell mediated immunity: carried out by T cells and occurs at the cellular level

    *

  • Clonal selection hypothesis: One of many B cells responds to a particular antigen and begins to divide, thereby producing a large population of identical B cells (a clone)

    *

  • *

  • *

  • Recognition of Self vs. NonselfFor the immune system to respond to foreign substances, it must distinguish between host tissues and substances that are foreign to the host

    Self is normal host and nonself are foreign substances

    The clonal selection hypothesis (figure 17.5) and clonal deletion hypothesis (figure 17.6)

    This mechanism removes lymphocytes that can destroy host tissues and thereby creates tolerance for self

    *

  • Clonal Delection: this process,which takes place in the bone marrow and thymus, removes those lymphocytes that have receptors for self antigens

    *

  • Properties of Antibodies (Immunglobulins)Y-shaped protein molecules composed of four polypeptide chains two identical light (L) chains and two identical heavy (H) chains

    Constant regions: determines the particular class that an immunoglobulin belongs to

    Variable regions: each chain have a particular shape and charge that enable the molecule to bind a particular antigen

    *

  • Antibody Structure

    *

  • *

  • *

  • Classes of ImmunoglobulinsFive classes of immunoglobulins have been identified in humans and other higher vertebrates

    IgG: the main class of antibodies found in the blood accounts for as much as 20% of all plasma proteinsIgA: occurs in small amounts in blood and in larger amounts in body secretions (tears, milk, saliva and mucus)IgM: found as a monomer on the surface of B cells and is secreted as a pentamer by plasma cellsIgE: has a special affinity for receptors on the plasma membranes of basophils in blood or mast cells in tissuesIgD: found mainly on B-cell membranes and is rarely secreted

    *

  • How B Cells Build Diverse Antibodies

    *

  • The Structures of the Different Classes of Antibodies

    *

  • *

  • *

  • *

  • *

  • Primary and Secondary ResponsesIn humoral immunity the primary response to an antigen occurs when the antigen is first recognized by host B cells

    Primary response of B cells can occur by two mechanisms:

    B cells can be activated by binding antigen, proliferating and forming plasma cells (T-independent antigens)Produces IgM antibody and no B memory cells are formed (T-dependent antigens)

    Secondary response: when an antigen recognized by memory cells enters the blood

    *

  • Primary and Secondary Responses to an Antigen

    *

  • Primary and Secondary Responses to an Antigen

    *

  • Antibodies produced by humoral immune responses eliminate foreign agents in three ways:NeutralizationOpsonizationImmune complexes

    *

  • Summary of Humoral Immunity

    *

  • Monoclonal AntibodiesAntibodies produced in the laboratory by a clone of cultured cells that make one specific antibody

    Myeloma cells (malignant cells of immune system) are mixed with sensitized lymphocytes

    Lymphocytes are used because each makes a particular antibody

    Hybridoma: when two cell types are mixed in cultures, they can be made to fuse with one another to make this cell type

    *

  • Production of monoclonal antibodies: only the hybridoma cells grown in culture will survive, because any unfused spleen cells cannot divide, and any unfused mouse myeloma cells cannot get the nutrients they need to grow

    *

  • *

  • *

  • Cell-Mediated ImmunityInvolves the direct actions of T cells

    T cells interact directly with other cells that display foreign antigens

    Involves the differentiation and actions of different types of t cells and production of chemical mediators (cytokines)

    Cytokines: lymphokines and interleukins

    *

  • The Reactions in Cell-Mediated Immunity

    *

  • *

  • Cell-Mediated Immune ReactionInvolves the response of T lymphocytes

    T cells cannot be activated directly by antigens

    Macrophages that have processed an antigen secrete the lymphokine interleukin-1 (IL-1), which activates T helper cellsT helper cells secrete interleukin-2 (IL-2) and activate delayed hypersensitivity cells and cytotoxic killer cellsIL-1 and IL-2 cause undifferentiated cells to become natural killer cells

    *

  • Types of T cells: After T cells are challenged by antigens, the cells differentiate into one of several types of functioning T cells

    *

  • Summary of Cell-mediated Immunity: CD stands for cluster of differentiation

    *

  • Active immunization is the process of inducing active immunity

    Can be conferred by administering vaccines or toxoids

    Vaccine: a substance that contains an antigen to which the immune system responds

    Toxoid: an inactivated toxin that is no longer harmful, but retains its antigenic properties

    Immunization

    *

  • Recommended ImmunizationsThree vaccines that immunize against seven diseases are currently recommended in the U.S

    DTaP vaccine: contains diphtheria toxoid, acellular pertussis (whooping cough), and tetanus toxoidPoliomyelitis vaccineMMR vaccine contains live rubella, rubeola, and mumps virus

    *

  • Vaccination mark from inoculation with BCG vaccine: This vaccine is used in some countries to immunize against tuberculosis

    *

  • Passive ImmunizationReady-made antibodies are introduced into an unprotected individual

    Because antibodies are found in serum, these products are often called antisera

    Established by administering a preparation such as gamma globulin, hyperimmune serum, or an antitoxin that contains large numbers of ready-made antibodies

    *

  • Colorized SEM of a small T lymphocyte attacking two large tumor cells

    *

  • How the Immune System Combats Viruses

    *

  • *

  • *

  • *

  • *

  • How Antigens of Parasitic Protozoans Thwart the Immune System

    *

  • *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *

    *