chapter 9 (1)

Immunology

Study of the human system and immune response

Immunogen

Any substance capable of inducing an immune response whether humoral or self-mediated

Antigen

Substance detected by the B cell or T cell that acts as target of immune response

Antibody (Ab)

also known as an immunoglobulin (Ig), protein produced by plasma cells used by the immune system to neutralize pathogens such as pathogenic bacteria and viruses.

Epitope

Antigen structure recognized by the B cell or or T cell

Hapten

substance with low molecular weight that can only induce an immune response if bound to immunogenic substance (carrier molecule)

antigen

is a harmful substance which enters the body which causes it to make antibodies as a response to fight off disease

antigen

structures specifically bound by antibodies or a cell surface version of Ab ~ B cell antigen receptor

Immune System

• complex network of cells and proteins that defends the body against infection.

• keeps a record of every germ (microbe) it has ever defeated so it can recognize and destroy the microbe quickly if it re-enters the body.

• made up of organs that control the production and maturation of certain lymphocytes.

• Bone marrow and the thymus areprimary lymphoid organs. The bone marrow produces defense cells.

Immunity

Ability to resist damage from pathogens like microorganisms; harmful chemicals like toxins and internal threats such as cancer cells

nonspecific components

barriers or eliminators of a wide range of pathogens irrespective of their antigenic make-up.

Innate Immune System

made of defenses against infection that can be activated immediately once a pathogen attacks.

Natural Active Acquired Immunity

Antibodies developed in response to an infection

Artificial Active Acquired Immunity

Antibodies developed in response to a vaccination

Natural Passive Acquired Immunity

Antibodies received from mother e.g. through breast milk

Artificial Passive Acquired Immunity

Antibodies received from a medicine e.g. from a gamma globulin injection or infusion

Active Acquired Immunity

Develops in response to an infection or vaccination

Passive Acquired Immunity

Develops after you receive antibodies from someone or somewhere else

Acquired Immunity

Immunity that develops during your lifetime

Innate Immunity

Organs, tissues, and cells of the immune system that you are born with

Chemical Mediators

chemicals on the surface of cells destroy pathogens or prevent their entry into the cell. Eg: lysosomes, mucus, histamine

WBC

Produced in the red bone marrow & lymphatic tissue and released into the blood.

Chemotaxis

the movement of WBC towards the chemicals (complement, histamine)

Basophils

Motile WBC leaving the blood and enter infected tissues; derived from Red Bone Marrow.

Mast Cells

Non motile cells in connective tissue near capillaries, gastrointestinal tract, urogenital tract.

Natural Killer Cells (NK)

Account for up to 15% of lymphocytes

Recognize classes of cells such as tumor or cells infected by specific virus

self antigen

molecules body produces to stimulate an immune system response.

Adaptive Immune System

also known as the acquired immune system is a subsystem of the overall immune system that is composed of highly specialized, systemic cells and processes that eliminate pathogens or prevent their growth.

Cytokines

are a large group of proteins secreted by specific cells of immune system. Cytokines are signaling molecules that mediate and regulate immunity, inflammation and hematopoiesis.

◦ Ex. interferon,interleukin,and growth factors

Cell-Mediated Immunity

◦ does not involve antibodies.

◦ the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to antigen.

Helper T Cells

◦ most important cells in adaptive immunity

◦ they are required for almost all adaptive immune responses.

◦ They help activate B cells to secrete antibodies and macrophages to destroy ingested microbes.

◦ they also help activate cytotoxic T cells to kill infected target cells.

ANtibody

• also known as immunoglobulins,

• Y-shaped proteins produced by the immune

  system to help stop intruders from harming the body.

• When an intruder enters the body, the immune system is put into action.

• These invaders, which are called antigens, can be viruses, bacteria, or other chemicals.

complement system

also known as complement cascade

◦enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism

◦promote inflammation, and attack the pathogen's cell membrane.

Hypersensivity Reaction

• a condition in which the normally protective immune system has a harmful effect on the body.

• Exaggerrated and inappropriate immune response

Allergy

an abnormal immunological response to an otherwise harmless environmental stimulus (e.g., food, pollen, animal dander)

Hypersensitivity Reaction

• Occur when already sensitized person is re-exposed to the same foreign antigen

• Activated chemical mediator & Complement system

Type I: Immediate (Anaphylactic) Hypersensivity

allergic reaction provoked by re-exposure to a specific type of antigen referred to as an allergen.

Exposure may be by ingestion, inhalation, injection, or direct contact.

Local anaphylaxis (food allergy, urticaria, eczema, rhinitis)

Type II Hypersensitivity

involves IgG or IgM induced damage to self cells (Cell-surface or Matrix Antigen