Immunity

• Innate immunity


  Present at birth, first-line defense against pathogens
• Three lines of defense


  • Skin surfaces (mucous membranes, enzymes, microbial flora)
  • Activities of lymphocytes, granulocytes, macrophages
  • Antibodies of T lymphocytes, B lymphocytes, from acquired immunity.
• Four types of acquired immunity

  • Natural active acquired immunity
  • Natural passive acquired immunity
  • Artificial active acquired immunity
  • Artificial passive acquired immunity
• Natural active acquired immunity


  After introduction of a foreign antigen results in formation of antibodies or sensitized T lymphocytes
• Artificial active acquired immunity


  Occurs with immunization
• Artificial passive acquired immunity


  Occurs when receiving a specific transfusion. For example: immunoglobulin (Ig)
• Natural passive acquired immunity


  Antibodies from a mother to fetus through the placenta or from the colostrum or breast milk. (It is immediate but short lived)
• Lymphoid system


  • Spleen
  • Thymus
  • Bone marrow
  • Adenoids
  • Tonsils
  • Appendix
• Lymphatic system


  Along with blood connects organs
• IgG


  In blood (80-85%), may enter tissue, selectively crosses placenta, binds to macrophages and neutrophils, predominates the secondary and late immune response
• IgD


  Found in the cell membrane of B lymphocytes
• IgM


  In blood. Kills bacteria. First antibody produced with initial immune (primary) response
• IgA


  Protects entrances to the body, found in high concentrations in body fluids. Primarily released in mucus secretions and is particularly useful in defending the airways. Also found in breast milk
• IgE


  Forms a receptor on masts cells and basophils and triggers histamine release during allergic reactions (found in trace amounts)
• Cells of immune responses

  Made in the bone marrow
• Myeloid progenitor


  • Neutrophils
  • Monocytes
  • Eosinophils
  • Basophils
  • Mast cells
• Lymphoid progenitor


  • B lymphocytes in liver
  • Mature T lymphocytes
  • T killer cells
• Antibody mediation process

  1. Exposure

  2. Detection

  3. Sensitization

  4. Antibody production

  5. Binding

  6. Cellular events

  7. Re-exposure
• Exposure


  Invasion in which our body reacts and stimulates immune response
• Detection


  Antigen is detected by macrophages and presents it to the B lymphocyte
• Sensitization

  B cell becomes sensitized and divides into plasma cells (antibodies), and memory cells that wait for the second exposure
• Antibody production

  Antibodies look for antigens (IgG IgM)
• Binding

  Antibodies bind to antigen and detects the foreign body
• Cellular events

  Antibodies binding causes events and attracts leukocytes which result in neutralization
• Re-exposure


  Memory cells recognize the antigen and rapidly divides for immune response
• Immune system production of T and B cells

  1. Bone marrow produces lymphoid

  2. Thymus and bone marrow produce T and B cells

  3. T cells go into the spleen

  4. B cells into the lymph nodes

  5. T helper cells bring antigens to memory T and B cells

  6. T helper cells encourage other cells and help activate B lymphocytes
• Dendritic cells


  Promote proliferation of CTLs and Helper T cells by serving as antigen presenting cells
• T lymphocytes


  • Key role in attacking infected cells and fighting viruses
• Cytotoxic T cells


  • Directly kill foreign antigens
• Helper T cells


  • Regulate cytotoxic T and B cell responses producing cytokine messengers to intensify immune response
• B lymphocytes


  • Plasma cells differentiated by exposure to an antigen. Responsible for body's response to invading bacteria and viruses
• Infancy

  Increases exposure to antigens
• Immunity responsedeclines with...

  Age, can lead to more serious complications, lessened vaccine efficacy
• Primary immunodeficiency


  Entire immune system is inadequate
• Secondary immunodeficiency

  Immune function loss is due to treatments of illness. Ex transplanted tissue and treatment for leukemia
• Types of hypersensitivity

  • Rapid sensitivity to allergens on first exposure
  • Cytotoxic reactions: antibodies going against a blood transfusion
  • Complex mediated deposits in tissue
  • Delayed hypersensitivity like poison ivy
• Type one hypersensitivity

  1. Person is exposed to allergen

  2. Antibodies are formed by B cells which produce a large amount of IgE

  3. Mast cells have IgE attached to them which then reacts to the allergen on the second exposure

  4. This triggers the release of chemical mast mediators like histamine
• Anaphylactic responses

  • NEUROLOGICAL (Headache, dizziness, paresthesia)
  • SKIN (pruritus, angioedema, erythema, urticaria.)
  • RESPIRATORY (coughing, wheezing, dyspnea, respiratory arrest, narrowed airway.)
  • CARDIOVASCULAR (hypotension, Dysrhythmia, tachycardia, cardiac arrest)
• Assessments and treatments for hypersensitivity


  1. Identify suppressed or exaggerated immune system

  2. Diagnostic tests like blood tests

  3. Screening
• Primary preventions for hypersensitivity

  1. Vaccination

  2. Modify risk factors