Disease and the Immune System

1. Disease and the Immune System

2. Disease • is any change, other than an injury, that disrupts the normal functioning of the body. It is the inability to maintain homeostasis.

3. Causes • Inheritance: sickle-cell anemia, hemophilia • Toxic Substances: cigarette smoke, alcohol • Poor Nutrition: ricketts, anorexia, scurvy • Organ Malfunction: heart disease, diabetes • Personal Behavior: drug addiction, alcoholism

4. Causes continued • Pathogens: organisms that enter the body and cause infectious diseases • Antigens • Toxins that pathogens produce that cause harm to an organism. • Virus • Protein shell • DNA or RNA

5. Examples of Viruses

6. Virus uses the host cell to reproduce

7. Examples of diseases caused by viruses: mono, flu, common cold, chicken pox, small pox, pertussis, AIDS small pox AIDS chicken pox

8. Pathogens continued: • Bacteria: Tuberculosis, E. coli, cholera, tetanus E. coli cholera tuberculosis tetanus

9. c)Fungi: ringworm, athlete’s foot, jock itch ringworm athlete’s foot

10. d)Parasites: lice, malaria, dysentery, tapeworm, schistosomiasis lice tapeworm Amoebic dysentery malaria in red blood cells schistosomiasis

11. What is Immunity?

12. Immunity • Immunity • The ability of the body to fight infection and/or foreign invaders by producing antibodies or killing infected cells. • Immune System • The system in the body responsible for maintaining homeostasis by recognizing harmful from nonharmful organisms and produces an appropriate response.

13. Parts of the Immune System • Blood - White Blood Cells in particular. • Lymph nodes • Thymus Gland – Produces T Lymphocytes • Bone Marrow – Produces B Lymphocytes

14. How does the body fight infection/foreign invaders? The Body’s THREE lines of Defense First Line of Defense – The Skin • Provides Physical and Chemical barriers • Physical – hard to penetrate, made of indigestible keratin • Chemical – tears, sweat

15. Second Line of Defense – Nonspecific Immune Response These are defenses the body uses no matter what the invader may be. These defenses include: • Phagocytosis – done by Macrophages • Natural Cell Killers • Inflammation - caused by release of Histamine from leukocytes • Fever – caused by histamines. The fever (high temp) kills invaders by denaturing their proteins. Macrophage: A phagocytic cell found in the liver, spleen, brain and lungs. Travels to all areas of the body to find and eat pathogens.

17. Third Line of Defense –Specific Immune Response This is a specific response to a specific pathogen/antigen. • The response involves the creation of Antibodies.

18. Antibodies • Y-shaped protein molecule. • Made up of variable and constant regions. • Made up of Heavy and Light chains. • Produced by B-Lymphocytes • Function: Recognize antigens, bind to and deactivate them. • Note: Variable region recognizes the anitgens.

19. How an antibody operates/works? Deactivation of a bacterium by an antibody.

20. The Pathway of Specific Immune Response Step 1 Pathogens eaten by Macrophage Step 2 Displays portion of Pathogen on surface Step 3 Pathogens Helper-T cell recognizes Pathogen

21. Activates B- Cell Activates Cytotoxic T- Cell Memory B-Cell Memory T-Cell Antibodies Kills Infected Cells

22. Carried out by T-Cells Infected cells are killed by Cytotoxic T –Cells. Carried out by B-cells Antibodies are produced and dumped into blood stream. Antibodies bind to antigens and deactivate them. Cellular Immunity .vs. Antibody Immunity Cellular Immunity Antibody or Humoral Immunity

23. Immune Response Explained • Antigen infects cells. • Macrophage ingests antigen and displays portion on its surface. • Helper T- Cell recognizes antigen on the surface of the macrophage and becomes active. • Active Helper T-Cell activates Cytotoxic T-Cells and B-Cells. • Cytotoxic T-Cells divide into Active Cytotoxic T-cells and Memory T – Cells. • Active Cytotoxic T-Cells kill infected cells. • At the same time, B-Cells divide into Plasma Cells and Memory B- Cells. • Plasma cells produce antibodies that deactivate pathogen. • Memory T and Memory B cells remain in the body to speed up the response if the same antigen reappears. • Suppressor T-Cells stop the immune response when all antigens have been destroyed.

24. Immune Response Summary Displays copy of antigen on surface of cell Antibody Immunity Cellular Immunity

25. Primary .vs. Secondary Immune Response • Primary Immune Response • This is a response to an invader the First time the invader infects the body. • No measurable immune response for first few days. • Next 10 – 15 days antibody production grows steadily • Secondary Immune Response • A more rapid response to an invader the 2nd time it invades the body. • Antibody production increases dramatically and in a much shorter time period..

26. Primary .vs. Secondary Immune Response

27. Passive .vs. Active Immunity • Active Immunity This is immunity where the body is “actively” producing antibodies to fight infection. Ex: You have a throat infection and you are actively creating antibodies to fight it. Vaccination: An injection of a weakened strain of an infectious microbe (pathogen) that causes the body to undergo active immunity (produce antibodies). • Passive Immunity This is immunity where antibodies are given to a person from the blood of another person or animal. This immunity only lasts for a short period of time. ex: Breastfeeding mothers pass antibodies to their children through the milk. ex: Vaccines against tropical diseases like cholera & typhoid

28. Man-made treatments for diseases • Antibiotics • Produced by certain organisms that destroy bacteria. Can slow down reproduction • Ex. Penicillin, made from a kind of mold, interferes with the production of the cell walls of the bacteria • Cannot be used against viruses. Some drugs can be used that interrupt the viruses life cycle, so prevents virus from entering the host cells.

29. Autoimmune Disease • Autoimmune diseases are diseases where the immune system begins to attack itself. • Ex: • Rheumatoid Arthritis – crippling disease of the joints. • Lupus – disease of blood and organs. • Multiple Sclerosis – disease of nervous system • Cause(s): unknown • Cures/Treatments: No known cures. Usually treated with drugs.

30. Allergies Allergy - An exaggerated response by the immune system to an allergen. Allergen: a normally harmless substance that causes an allergic reaction. ex: dust, pollen, mould, food, insect stings Types of Allergic reactions There are two types of allergic reactions. a. Immediate – occurs within seconds and normally lasts for about 30 mins. b. Delayed – takes longer to react and can last for a much longer time.

31. What happens during an allergic reaction? • During an allergic reaction antibodies cause histamines to be released from certain cells. Histamines cause: a. Swelling of tissues b. Release of fluids (runny noses and eyes) c. muscle spasms (some cases) Anaphylaxis or anaphylactic shock: This is the sudden and severe allergic reaction to a substance that can cause death. Treatments for Allergies • Avoidance of material – especially food. • Epinephrine – “epi – pen” • Antihistamines -- benadryl

32. HIV and AIDS HIV particles (grey) covering a white blood cell. This Powerpoint is hosted on www.worldofteaching.com Please visit for 100’s more free powerpoints

33. HIV History • HIV is thought to have entered into humans somewhere between 1914 and 1940. • In 1983, a retrovirus, now called human immunodeficiency virus (HIV), had been identified as the cause of AIDS. • The HIV antibody test has be used to screen all blood supplies in the U.S. since 1985. • People receiving blood or blood products before 1985 may have been infected.

35. HIVHuman Immunodeficiency Virus • HIV infects the immune system cell called the Helper T cells (-most important white blood cell involved in identifying infections.)

36. AIDSAcquired Immune Deficiency Syndrome • The immune crippling disease caused by the HIV virus in which the body becomes unable to protect itself against any secondary infections.

37. Body Fluids with High Concentrations of HIV • Blood • Semen/Vaginal fluids (as high as blood) • Breast milk • Pus from sores

38. Low concentrations of HIV It is highly unlikely you will be infected if you come into contact with: • Sweat • Tears • Urine • Saliva (-highly possible if blood from mouth sores is present)

39. How is HIV Spread? • ANY type of sexual activity (highest risk) • Sharing used drug needles • Pregnancy-from mother to child • Sharing razors- if blood is present • Kissing- if even the smallest amount of blood is present. (-membranes of mouth are thin enough for HIV to enter straight into the body.) • Tattoos/body piercing if equipment is not clean.

40. How is HIV not spread? • Shaking hands • Hugging • Swimming pools • Toilet seats • Insect bites • Donating blood

41. Can HIV be cured? • NO! Drugs are available to manage the disease, but HIV stays in the body forever! • PROBLEM: RNA viruses mutate at a very high rate. A person with HIV under control can evolve resistance to the drug treatments. • Some infected persons have several strains of HIV in their bodies.

42. What does HIV look like? • Initial infection- flu like symptoms a few weeks after infection. • Stage 1-HIV positive with no symptoms- can stay at this stage for up to 10 years, but still can pass on the virus. • Stage 2-HIV positive with symptoms- at this point the person is said to have AIDS. Symptoms include: • swollen glands, chronic diarrhea, loss of weight and appetite, fever, fatigue, skin rashes (lesions), night sweats, oral thrush. Life expectancy: 2 to 5 years.

43. Death and AIDS • Stage III-Full blown AIDS- • Person dies of rare opportunistic infections that take advantage the weakened immune system: • Person dies in a matter of months. • AIDS related illnesses include rare cancers and Pneumonia.

44. Stages of HIV Infection