1. Immunology We have specific and a non-specific response sytems Non-Specific = barriers, like skin and mucus, HCl in the stomach, and phagocytosis. Specific = Immune system and antibodies

2. Phagocytosis – using Lytic Enzymes (hydrolysis) Absorption

3. Role of Histamine Histamine is a hormone which is released at a damaged site Inflammation causes dilation of blood vessels More phagocytes are delivered to the damaged area.

4. The Specific Response Slower than the Non-Specific Longer lasting Responds to ANTIGENS - Proteins/Glycoproteins (see cell membrane notes) on the cell surface membrane which trigger an immune response. Utilises white blood cells-LYMPHOCYTES (B and T Lymphocytes)

5. B Lymphocytes – from stem cells in bone marrow

6. T Lymphocytes Made in the Thymus Gland.

7. Two types of Specific Immunity Cell-Mediated Response (uses T Lymphocytes) Humoral Response (uses B Lymphocytes)

8. Cell Mediated Response. This is a response that occurs when our cells have been infected – e.g. by a virus Infected cells (and macrophages) display the foreign antigens on their cell surface membrane One of our many T-helper cells will be complementary to these antigens

9. The T-helper cells stimulate the cloning of cytotoxic T cells Complementary shapesAntigen of pathogen Chemicals are released which cause MITOSIS of the correct cytotoxic T cells

10. Mitosis of T cells Stimulated by the T-helper cells Cloning of Killer T cells

11. How T cells protect us They kill infected cells by producing a protein which destroys the cell membrane They stimulate Phagocytes They stimulate B cells to divide They form T memory cells

12. Cell-Mediated Immunity YouTube - Cell Mediated Immune Response

13. The Humoral Response This process involves B Lymphocytes and the production of antibodies It begins in the same way as the cell- mediated response.

14. Complementary shapes Antigen of pathogen Chemicals are released which cause MITOSIS of the correct cytotoxic T cells AND B CELLS B Cell cloning occurs by mitosis B Cell Antigen of pathogen Cytokines released by T helper cells This cell could be a B cell or a macrophage

15. B Cells Cloned B Cells can form PLASMA CELLS or MEMORY CELLS Plasma Cells – produce Antibodies

16. Antigen presenting by B cell or macrophage Cloning/Mitosis Complementary B cell Produces antibodies Complementary T-helper cells will release chemicals to stimulate mitosis

17. B Memory Cells Stay in our tissues for many years. They carry out mitosis immediately upon contact with the complementary antigen A very quick, secondary response We do not become ill The same process with T memory cells

18. So, how do vaccines work?

19. Humoral Response YouTube - Antibody Mediated Immune ResponseYouTube - Antibody Mediated Immune Response

20. Summary of both types of Immunity YouTube - Review of Antibody and Cell- mediated ImmunityYouTube - Review of Antibody and Cell- mediated Immunity

21. Antibodies

22. Definition of antibody An immunoglobulin protein that is produced by B plasma cells in response to non-self antigens.

23. The Antigen-Antibody Complex The antibodies attach to the antigen on the pathogen and destroy it. MUST be a Complementary variable region!

24. Funny animation link YouTube - Immune System Animation

25. Why do we get flu more than once? Antigenic Variability! Some antigens constantly change (mutation) Memory cells are no longer complementary The Primary Response is initiated instead of the secondary response.

26. Pathogens have many antigens So we produce many different types of antibody – POLYCLONAL antibodies Scientists can clone antibodies in the laboratory They can clone just one kind at a time These are MONOCLONAL antibodies

27. Monoclonal Antibodies These antibodies are complementary to a specific protein. Can be used to mark and identify proteins in blood or urine E.g. in Pregnancy tests, or drug tests in athletes

28. Uses in cancer treatment Cancer cells will present antigens on their surface membrane Specific monoclonal antibodies will attach to these cells and can activate a cytotoxic drug to kill the cell.

29. Uses in Transplant Surgery Transplanted organs often suffer rejection from the action of our T Cells Monoclonal antibodies can attach to and “knock out” these T Cells.

30. Other use The monoclonal antibody can be used to label and separate a chemical in a mixture. Read pages 110-111 and discuss the ethical issues associated with monoclonal antibodies, and how society uses scientific knowledge to inform decision-making.

31. Vaccines You should now understand how vaccines work. But what makes a successful vaccine?

32. A Successful Vaccination Programme Must be economically viable to produce enough for a vulnerable population Have few side-effects Easy to store and transport Trained staff must be available It must be possible to carry out HERD IMMUNITY i.e. to immunise a total population

33. Evaluating vaccines They may not eliminate a disease because... -Individuals may have a poor immune system -Disease may spread BEFORE the vaccine has produced the required memory cells -The pathogen could mutate -There may be too many antigens on the pathogen (e.g. cold virus / HIV) -People may object –e.g Religion, MMR

34. Cholera and TB Vaccine Evaluation Cholera has high antigenic variability Populations are now more mobile so diseases spread much more easily HIV cases have risen so more people get TB Poverty and wars create overcrowded conditions so TB cases have risen More elderly people so more TB.

35. Now complete the Application questions!