Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Memmler’s The Human Body in Health and Disease 11 th edition Chapter 17 Body Defenses, Immunity, and Vaccines

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Objectives List factors that determine the occurence of infection Differentiate between nonspecific and specific body defenses with examples Describe the inflammatory reaction List several types of innate immunity Define antigen and antibody Compare T-cells and B-cells Explain macrophages and their role in immunity Describe some protective effects of an antigen-antibody reaction Differentiate between natural and artificial adaptive immunity Differentiate between active and passive immunity Define the term vaccine and give several examples of vaccines Define immune system and give examples List several disorders of the immune system Explain the possible role of the immune system in preventing cancer

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Immune System Types: Nonspecific defenses –Effective against any harmful agent Specific defenses –Effective against a certain agent only

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Why Do Infections Occur? Factors - Portal of entry Virulence of organism –Aggressiveness –Toxin production Number of pathogens Predisposition

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The body’s defense occurs in a series… Chemical and Mechanical barriers Phagocytosis Natural Killer Cells Inflammation Fever Interferon Nonspecific Defenses Innate Immunity Adaptive Immunity The Antigen-Antibody Reaction Artificial Adaptive Immunity Specific Defenses

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Chemical and Mechanical Barriers Skin Mucous membranes –Cilia Body secretions –Tears –Perspiration –Saliva –Digestive juices Reflexes –Sneezing –Coughing –Vomiting –Diarrhea

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Phagocytosis -White blood cells take in and destroy waste and foreign material. Examples: Neutrophils Macrophages

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Natural Killer Cells (Type of lymphocyte) Can recognize body cells with abnormal membranes Found in lymph nodes, spleen, bone marrow, blood Secrete protein that breaks down cell membrane

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Inflammation Inflammatory reaction –Heat, redness, swelling, pain –Cells release histamine –Leukocytes enter tissue Granulocytes, macrophages, mast cells –Leukocytes and plasma produce inflammatory exudate –Pus is produced –Lymph nodes enlarge

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Fever (As phagocytes work, they release substances that raise body temperature) Fever boosts the immune system in several ways: Stimulates phagocytes Increases metabolism Decreases some organisms’ ability to multiply *** remember…..fever is not always bad.

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Interferon Group of substances that prevent nearby cells from producing more virus Also acts nonspecifically on immune system cells Used in treatment of viral infections, certain types of cancer, and MS

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins ImmunityImmunity (The final line of defense) Defined as: the power to overcome a specific disease agent Types: Innate immunity –Inherited in genes Adaptive immunity –Develops after birth –Acquired naturally or artificially –Active or passive

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Types of immunity

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Innate Immunity Species immunity Individual immunity

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Adaptive Immunity Develops in a person During lifetime From encounters with specific harmful agents

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Antigens Defined as : any foreign substance that enters the body and induces an immune response -Can be found on the surface of pathogens, RBC’s, tissue cells, pollen, toxins and food -The thing to realize and remember about antigens….. it stimulates the activity of T-cells and B-cells

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins T Cells Originate as stem cells in bone marrow Change to T cells in thymus Become sensitized to specific antigens Produce cell-mediated immunity –Cytoxic T cells –Helper T cells –Regulatory T cells –Memory T cells Macrophages – ingest the original foreign antigen, breaks it down, exposes it to the surface so T-cells can bind with it and then releases interleukins which stimulates other WBC’s

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Activation of a helper T cell by a macrophage (antigen- presenting cell).

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins B Cells and Antibodies Antibody (also known as immunoglobulin) is substance produced in response to antigen Manufactured by B cells (B lymphocytes) Must mature in fetal liver or in lymphoid tissue Provides humoral immunity Contained in gamma globulin fraction of blood plasma

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Activation of B cells. The B cell combines with a specific antigen. The cell divides to form plasma cells, which produce antibodies. Some of the cells develop into memory cells, which protect against reinfection.

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Antigen–Antibody Reaction Complement is an enzyme that assists in immunity. How? Coats foreign cells Destroys cells Promotes inflammation Attracts phagocytes ***LOCK AND KEY

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Naturally Adaptive Immunity Immunity acquired through contact with a specific disease organism Active immunity Passive immunity Active Example: Malaria

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Artificially Adaptive Immunity Vaccination (immunization) can cause a person’s immune system to manufacture antibodies Preventive measure Risk of side effects

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Types of Vaccines Live Attenuated Toxoid Killed by heat or chemicals Antigenic component Genetically engineered

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Boosters Active immunity does not always last a lifetime Repeated inoculations (booster shots) help maintain high titer of antibodies in the blood Number and timing varies with vaccines

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Examples of Vaccines Whooping cough (pertussis) Diphtheria, tetanus toxoid (Td) Haemophilus influenzae type B (Hib) Pneumococcal vaccine (PCV) Viral –Inactivated polio, oral polio –Measles (rubeola), mumps, rubella (MMR) –Hepatitis B –Hepatitis A –Chicken pox (varicella); vaccine for shingles now available for those >60 yr –Influenza –Rabies –Rotavirus –HPV (human papillomavirus) for girls 11-26

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Artificial Passive Immunity Acquired by administration of immune serum (antiserum) Short-lived immunity Used in emergencies Often derived from animals May cause sensitivity reaction

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Disorders of the Immune System Resulting from overactivity –Allergy –Autoimmune disease Resulting from underactivity –Hereditary –Infections –Environmental

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Allergy A tendency to react unfavorably to certain substances that are normally harmless to most people Factors –Disease –Loss of immune system control –Cross-reaction of antibodies and self antigens Treatments –Immune-suppressing drugs –Chemotherapy/stem cell replacement

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Immune Deficiency Diseases Autoimmunity : an abnormal reactivity to one’s own tissue (involves a long list of diseases….Ex: MS, lupus, and IBS) Failure of immune system May involve any part of system Varies in severity Congenital or acquired (e.g., AIDS) HIV –A retrovirus; uses reverse transcriptase enzyme

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Multiple Myeloma Cancer of blood-forming bone marrow cells Treatment –Chemotherapy –Bone marrow transplants

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins The Immune System and Cancer Immune surveillance –Declines with age Immunotherapy –T cells activated with interleukin –Vaccines

Copyright © 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins Transplantation and Rejection Syndrome Caused by normal antigen–antibody reaction (the normal reaction is called rejection syndrome) Reduced by –Tissue typing (except in corneal transplants) –Immune suppression drugs (suppress synthesis of nucleic acids, drugs, and hormones)