1. Immune System: Autoimmune Diseases

2. Review Question What is the function of T-cells?

3. Review Question What is the function of B-cells?

4. Review Question What is the difference between natural and artificial immunity?

5. Review Question What is the difference between active and passive immunity?

6. Vaccination A preparation containing antigenic material: Dead microorganism Weakened microorganism- virus can only reproduce a few times in body- can’t cause disease Part of virus or bacteria that contains antigen Toxoid (harmless form of toxin of bacteria)

7. Vaccination Why aren’t they always effective? Natural infections persist within the body for a long time so the immune system has time to develop an effective response, vaccinations from dead m-os do not do this. Less effective vaccines need booster injections to stimulate secondary responses

8. Vaccination Why aren’t they always effective? Some people don’t respond well/at all to vaccinations 1. Defective immune systems 2. Malnutrition, particularly protein

9. Vaccination Why aren’t they always effective? Antigenic variation caused by mutation Antigenic drift – mutations arise in genes for antibodies, new strains of virus created over time (Influenza) Antigenic shift – large changes- two or more strains combine, new virus has combo of antigens and is unrecognizable by host

10. Vaccination Why aren’t they always effective? No vaccines against protists (a protist causes malaria) Many stages to Plasmodium life cycle with many antigens so vaccinations would have to be effective against all stages

11. Vaccination Why aren’t they always effective? Antigenic concealment parasites live inside body cells Plasmodium – liver and blood cells Parasitic worms – cover themselves in host proteins HIV – live inside T-helper cells, highly complex and changeable

12. Smallpox Symptoms Red spots containing transparent fluid all over body. Spots fill with pus Eyelids swell and become glued together

13. Smallpox Mortality 12-30% died Survivors often left blind and disfigured with scabs.

14. Smallpox Eradication program Started by WHO in 1956 Aimed to rid world of smallpox by 1977 Involved vaccination and surveillance Over 80% of populations at risk of the disease were vaccinated

15. Smallpox Eradication program After any reported case everyone in the household and 30 surrounding households vaccinated – RING VACCINATION Last case of smallpox reported in Somalia in 1977 World declared free of smallpox in 1980

16. Smallpox Eradication program – why was it successful? Variola virus stable  cheap as everyone used same vaccine Vaccine made from harmless strain of similar virus (vaccinia) Easy to identify infected people Smallpox doesn’t lie dormant in body

17. Smallpox Why wouldn’t an eradication program always work?

18. Smallpox Why wouldn’t an eradication program always work? Political instability Poor infrastructure Cost Difficult to diagnose before disease spreads Rapid mutation of disease

19. What happens when the body’s lymphocytes fail to recognize its own cells and tissues, and begin attacking them? AUTOIMMUNE DISEASES

20. Autoimmune Diseases Failure of antibodies and T cells to recognize own cells Antibodies and T cells launch attack against own cells Defenses either overreact to antigens or fail to react to an antigen

21. Hypersensitivity Hypersensitivity is an excessive response or overreaction of the immune system Types= allergy, autoimmunity, and isoimmunity

22. Allergy Hypersensitivity of immune system to harmless environmental antigens (allergens) Many are genetically predispositioned Susceptible person must be exposed multiple times to allergen- triggering production of antibodies

23. Allergy Exposure to allergen causes antigen-antibody reactions that trigger release of histamine and other inflammatory chemicals in body Histamine causes blood vessels to widen and become leaky.

24. Allergy Fluid and white blood cells leave capillaries. The area of leakage becomes hot, red and inflamed Antihistamines can be used to relieve symptoms

25. Allergy Are allergies all bad? Could there be benefits?

26. Allergy Allergies are not “bad”; but body’s way of protecting itself from potential harmful invaders Allergic reactions expel allergen from body Allergic reaction is like alarm system for body How would allergies have been helpful to our ancestors?

27. Allergy Many allergens can destroy cells (toxins, venom, etc) Body starts producing IgE (antibody) after first exposure of allergen starts harming your cells After you produce specific antibodies to the allergen, your body is oversensitive to it, prepared to immediately react and rid itself of the allergen if exposed again

28. Autoimmunity Incorrect and excessive immune response to “self- antigens” Body attacks itself Examples of diseases: Diabetes type 1 Hypothyroidism MS Rheumatoid arthritis Lupus

29. Isoimmunity Undesirable reaction of the immune system to antigens from different individual of the same species Can happen during: Pregnancy Organ or tissue transplant

30. Isoimmunity during pregnancy When antigens from fetus enter mother, sensitizing mother’s immune system Antibodies then form in the mother If they enter the fetus’ blood supply they can cause inappropriate immune reaction

31. Isoimmunity during pregnancy Erythroblastosis fetalis: Rh - mother and Rh+ fetus

32. Immune Deficiency Immunodeficiency= failure of immune system to defend against pathogens Normally disrupts function of B and T cells Allows more infections and cancer to form, that ultimately kill the patient Two types: Congenital and Acquired

33. Congenital Immune deficiency Rare; results from improper development of lymphocytes from birth Can cause insufficiency or absence of antibodies in blood Can be treated with antibody injections and bone marrow transplants

34. Acquired Immune Deficiency Develops after birth Best example: AIDS, caused by the virus HIV Human Immunodeficiency virus

35. HIV thought to have entered humans between 1914 and 1940 In 1983, the retrovirus was identified as the cause of AIDS HIV infects Helper T cells (most important WBC in identifying infections)

36. HIV Retrovirus containing RNA, high rate of mutation Tricks host cells into letting it into the Helper T cell Reverse transcription codes RNA into DNA New viral DNA gets spliced into cell’s DNA, taking over machinery of cell New HIV virions are synthesized and released from the cell

37. HIV Helper T cells die as HIV takes over the cell More lymphocytes are lost as disease progresses Some drug therapy exists to repress the spread of the virus by blocking its entrance into healthy cells or slowing its reproduction in the cell

39. What does HIV look like? Initial infection- flue 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 can still pass on virus (virus replicates slowly with drug therapy)

40. What does HIV look like? Stage 2-HIV positive with symptoms- T cell count= less than 200 per microliter of blood  person is diagnosed with AIDS Symptoms= swollen glands, diarrhea, loss of weight and appetite, fever, fatigue, skin rashes, night sweats, oral thrush Life expectancy= 2 to 5 years

41. What does HIV look like? Stage 3- Full blown AIDS Patient dies of infections that take advantage of weakened immune system Patient dies in a matter of months AIDS related illnesses include cancers and pneumonia