The Immune System: Antibodies and Vaccines

1. The Immune System: Antibodies and Vaccines Introduction to Biotechnology

2. The Immune System • Antigen - Any substance that gets in your body that isn’t supposed to be there. • Pathogen- a type of antigen that causes disease. • The immune system is your body’s defense against invaders (antigens). Protects you from disease. • Lymphocytes – white blood cells, the cells part of your immune system.

3. The Body's First Line of Defense • The immune system consists of organs, highly specialized cells, and a circulatory system that is separate from the blood vessels--all of which works together to clear infection from the body.

4. The Body's First Line of Defense • The organs of the immune system, positioned throughout the body, are called lymphoid organs. • The word "lymph" in Greek means a pure, clear stream--an appropriate description considering its appearance and purpose.

5. Lymphatic vessels • Lymphatic vessels and Lymph nodes form a circulatory system that operates in close partnership with blood circulation.

6. Lymphatic vessels/Nodes • Lymphatic vessels and lymph nodes are the parts of the special circulatory system that carries lymph, a transparent fluid containing white blood cells, chiefly lymphocytes. • Where white blood cells can meet foreign invaders aka germs aka anitgens

7. Lymph bathes the tissues of the body( sort of cleans then), and the lymphatic vessels constantly collect and move the lymph back into the blood circulation • Lymph nodes dot the network of lymphatic vessels and provide meeting grounds for the immune system cells that defend against invaders. • The spleen, at the upper left of the abdomen, is also a staging ground and a place where immune system cells confront foreign microbes aka germs aka antigens

8. Organs and tissues of the immune system dot the body in a protective network of barriers to infection.

9. Pockets of lymphoid tissue are in many other locations throughout the body, such as the bone marrow and thymus. Tonsils, adenoids, Peyer's patches, and the appendix are also lymphoid tissues.

10. All immune cells exit the lymphatic system and eventually return to the bloodstream. • Once in the bloodstream, lymphocytes are transported to tissues throughout the body, where they act as sentries on the lookout for foreign antigens.

11. White Blood Cells • There are four major types of white blood cells: Macrophage, Neutrophils, T cells, and B cells.

12. It’s all about the Bone Marrow • The immune system cells are produced in the bone marrow. • This nutrient-rich, spongy tissue is found in the center shafts of certain long, flat bones of the body, such as the bones of the pelvis. • The main types of lymphocytes are B cells, which grow to maturity in the bone marrow, and T cells, which start out in the bone marrow, but mature in the thymus located high in the chest behind the breastbone.

13. The Boss of the immune system T cells are the most important white blood cell; they coordinate the activities of all of the other white blood cells and are essential for fighting disease. T cells orchestrate, regulate, and coordinate the overall immune response. There are two major types of T cells: Helper T cells (TH) and Killer T cells(TK). Helper T cells send signals that activate the rest of your immune system to fight a germ. Killer T cells patrol the body and eliminate infected cells.

14. Certain T cells, which also patrol the blood and lymph for foreign invaders, can do more than mark the antigens; they attack and destroy diseased cells they recognize as foreign directly. • T cells depend on unique cell surface molecules (called epitopes – they’re the pieces that fit into the active sites like jigsaw puzzle pieces) to help them recognize antigen fragments.

15. B cells • B cells and or B-Lymphocytes make proteins called antibodies. • These antibodies circulate in the blood and lymph streams and attach to foreign antigens to mark/tag them for destruction by other immune cells

16. What are they? • Antibodies are also called immunoglobulins. • They are proteins that play a key role in our immune system – our defense against infection. • The study of which is immunology.

17. B Cell or B-Lymphocytes • There are millions of different B-lymphocytes, each producing a different antibody. • When an antigen bumps into a lymphocyte that matches it, the antigen is “handcuffed” by the antibody and tagged for destruction

18. Antibodies/Specificity • Specific antibodies fit specific antigens – like keys in locks. • The antibodies that B cells produce have an active site that is highly specific to target a certain antigen. • Antibodies bind tightly to parts of molecules that the body recognizes as foreign.

19. Antibodies/Specificity • Antibodies will bind to the epitope of the antigen • For example, they will bind to molecules on the surface of viruses or bacteria. • The fit between a given antibody and molecule is unique.

20. How do antibodies work? • Some antibodies coat the foreign invaders to make them attractive to the circulating phagocytes that will engulf the unwelcome microbe. • Some antibodies can block viruses from entering cells. • Some antibodies release a cascade of proteins which can destroy the foreign invaders.

21. How do antibodies work?

22. Macrophage • Macrophage (mack’-row-fage; from the Latin macro = big, • phage = eat) are white blood cells that eat germs that have been covered by antibodies. Their job is to patrol the body looking for germs. When they find an infection, they send a signal to our T cells, and our T cells send the other white blood cells to the infection.

23. Neutrophils • Neutrophils (new’-tro-fills) are the white blood cells that are • the “first responders” to infections. We have more neutrophils • than any other type of white blood cell.

24. Making lots of antibodies • Scientists isolate the B-lymphocytes that make the antibody we want • They combine that lymphocyte with special cells in the lab. • The result is a new type of cell that makes the antibody we want, and reproduces itself at a very high rate.

25. Monoclonal Antibodies • This means that in a relatively short time, we can create a pure supply of antibodies. • Antibodies created this way are called monoclonal antibodies.

26. Why Monoclonal Antibodies? • If you made a batch of monoclonal antibodies to a specific cancer cell, and injected them in a person with that kind of cancer, the antibodies would float through the body and “handcuff” those cancer cells. • These antibodies are harmless to normal cells.

27. Antibodies Go Everywhere • Because antibodies float throughout the body, they can track down and neutralize disease cells anywhere in the body. • We can attach radioactive or fluorescent molecules to monoclonal antibodies. • Then, we can locate disease centers or antigens, depending where the antibodies congregate.

28. Applications • Home pregnancy test kits are also biotechnology diagnostic products. • Tests for strep throat and many other infectious diseases provide results in minutes, enabling treatment to begin immediately in contrast to the two- or three-day delay of previous tests.

29. Applications • Drug testing • Monoclonal antibodies can be used to locate environmental pollutants. • They can also detect harmful microorganisms in food.

30. Applications • Therapeutic uses of biotechnology approved by the U.S. Food and Drug Administration (FDA) to date are used to treat many diseases, including anemia, cystic fibrosis, growth deficiency, rheumatoid arthritis, hemophilia, hepatitis, genital warts, transplant rejection, and leukemia and other cancers.

31. Immunity/memory • When your immune system knows what a certain germ( antigen) looks like, the next time that germ enters your body. • Your body can get rid of it faster and can get rid of it without you getting sick again. • You are then immune to that germ. • This occurs naturally as you encounter antigens • You can also be made immune

32. Vaccines • Are made from antigens that are usually proteins. • Vaccines for infectious disease are made by: • Old technology: Use the entire virus or bacterium in an inactive form. • New technology: Purify a particular protein from the surface of the virus or bacterium, and produce it in large quantities • This gives you man made immunity

33. Antibiotics • antibiotics- Kill only bacteria in our bodies.