IMMUNITY

1. IMMUNITY

2. Immunology deals with understanding how the body distinguishes between what is self and what is nonself; all the rest is technical detail.” (Benjamini et al.).

3. Consider…. • Man is one organism on this planet among millions… all of which are trying in their own way to maintain a foothold for survival, • Often the survival strategy operates at the expense of some other form. • Predation • Parasitism

4. WHAT IS A PATHOGEN?

5. Pathogens: Invading foreign organisms • Virus • Bacteria • Fungus • Protozoa • Helminthes (parasitic worms)

6. Virus • Bacteria • Fungus • Protozoa • Helminthes

7. Bacteria - prokaryotes • Coccus - round • Bacillus – rod • Spirillus - spiral

8. Antibiotics Natural - penicillin 1929: Alexander Fleming Interfere with bacterial life cycle Not actually used as medicine until 1945…Remember?

9. Viruses Living/Nonliving (borderline) The gray area  Parasitic -They need a host to reproduce and survive! (otherwise die or go dormant)

11. Virus • Enters host cell, • Sheds its protein covering • Viral genetic material takes control of cell • Tricks it into manufacturing more virus • Disrupts normal function of host cell

12. Infection: Invasion by pathogens • Local • Systemic

13. Toxins…… Produced by invading organisms or chemical pollutants

14. Routes of Infection 1) Penetration of skin 2) Penetration of mucous membranes 3) Inhalation of particles 4) Ingestion

15. Airborne Transmission: • Tuberculosis bacteria • Multicillin resistant staff • Influenza virus

16. Direct Contact: • Cold virus: hand to hand then hand to mouth • Most other respiratory infections

17. Food and Water-borne: Mouth to digestive tract bacteria dysentery protozoa bacteria diarrhea protozoa giardia

18. Body’s Defense System:

19. Your Immune System Levels of Immunity: • First Line of Defense PHYSICALBARRIERS The Skin, Mucus Membranes and Cilia • Inflammation Innate Responses Phagocytes plus other WBCs • Adaptive Immune Response  Cells with “memory” of past infections are released to defend invaders.

20. Physical and Chemical • Skin - largest organ of the body • Skin Flora • Sweat and Sebum • Mucous membranes on inside: • in gut • in lungs • Tear ducts

22. Immune System • Inflammatory response • Immune response

23. Development of White Blood Cells from Uncommitted Stem Cells.

24. White Blood Cells White blood cells, also called leukocytes, are continuously made in the bone marrow. There are a variety of leukocytes and they are all derived from hematopoietic stemcells. Leukocytes specific for immunity are called lymphocytes

25. Local Vs. Systemic Local Infection- The pathogen has caused an infection of tissues at surface of skin or mucous membranes. Systemic infection- From the skin or mucous membranes the pathogen enters either the bloodstream or lymphatic system…hence the name systemic

26. White blood cells - from bone marrow • Three groups of white blood cells are important • Macrophages: "big eaters" - phagocytic cells • Two types of Lymphocytes • 2. T cells • 3. B cells

27. Acquired Immunity is 1. antigen specific 2. Systemic 3. Has Memory (recognizes previous encountered pathogens)

28. Edema is the excess accumulation of fluids in tissue spaces. This can retard normal exchange of nutrients and metabolites. Filtration of the extracellular fluid exceeds drainage. Anything that causes increased capillary pressure, such as decreased plasma protein, increased capillary permeability or lymphatic blockage, can result in swelling and congestion of the extravascular compartment. EDEMA

30. Where Do We Get T and B? T stands for Thymus-dependent B stands for Bursa of Fabricius in which they were first discovered.

31. Where Do Lymphocytes Originate? • All Lymphocytes originate in the RED BONE MARROW called hematoblasts in a process called hematopeiosis. • Whether or not it becomes a B cell or a T cell depends on WHERE it become IMMUNOCOMPETENT (Capable of responding to a specific antigen) • Certain lymphocytes migrate to Thymus (these will become T cells as they undergo a maturation process under the direction of the hormone Thymosin.

32. Immunity: Ability to distinguish foreign substances Antigens: Foreign substances that trigger the immune response

35. Macrophages…. • Congregate in lymph nodes • Filter bacteria out of the lymph • When active, node fills with cells and swells • Macrophages can move through epithelium • Scavenge: clots • debris • dead tissue

36. Lymphocytes… • Travel in lymph system and blood stream • T cells: Cell Mediated Immunity • Helper T cells • Killer T cells • Suppressor T cells • B cells - Antibody Mediated Immunity • B cells • Plasma cells • Memory T and B cells

37. Recognition is based on Surface Receptors 1. Proteins on cell surfaces show "self" patterns to the immune system. It recognizes them and is not activated by them 2. Markers displayed on antigens are recognizable to the lymphocytes as foreign

38. Inflammatory Response • Tissue invaded locally • Release of histamines • Dilate blood vessels • Swelling • Fluid from capillaries • Increased heat • Redness • Macrophages move in • ……..INFLAMMATION!

39. Interleukin… • Peptide released by macrophages • Resets thermostat in hypothalamus • Causes fever • Interferes with viral activity

40. Interferon… • Secreted by virally infected cells • Stimulates adjacent cells to synthesize • antiviral proteins • Prevent adjacent cell from producing • macromolecules needed by the virus • Stimulates natural killer cells

41. Phagocytosis… • Neutrophyls- one can eat 20 bacteria • Monocytes- one can eat 100 bacteria

42. Immune Response… • 4 Phases • (1) Recognition • (2) Amplification of defense • (3) Attack • (4) Slow down

43. WHAT IS AN APC CELL? APC) stands for Antigen Presenting Cell. • Antigen-something,usually a protein or bacteria that is recognized by the body as foreign. • APC can be dendritic cell or macrophage; they chew up pathogens and place pieces of them ( antigens) on their cell membranes so that they can trigger a response from helper T cells.

44. What is an APC? • Antigen Presenting Cell (APC) • Antigen-something,usually a protein or bacteria that is recognized by the body as foreign. • APC can be dendritic cells or macrophages; they chew up pathogens and place pieces of them ( antigens) on their cell membranes so that they can trigger a response from helper T cells.

45. Phase I: Recognition • Dendritic Cells are drawn to site of injury; have eaten pathogen and PRESENTED their ANTIGENs on outside of cell surface. This is read by Helper T-Cells. • Antigen- a marker on the surface of a foreign substance that immune system cells recognize as non-self and trigger the immune response. • Helper T-Cells (CD4 cells) are lymphocytes (also produced in bone marrow) which activate killer Tc cells help B-cell produce antibodies.

46. Phase II: Amplification • Helper T cells (CD4 cells)- multiply rapidly and trigger the production of killer T cells and B cells in the spleen and lymph nodes. • Cytokines, chemical messengers secreted by the lymphocytes, help regulate and coordinate the immune response; interleukins and interferons.

47. Recognition… • Macrophages drawn to site • Consume foreign cells • Macrophages provide information about "invader" by displaying invader’s antigen on its cell surface

49. Amplification of Defense… • Helper T cells multiply rapidly • Helper T cells trigger production of • Killer T cells • B cells • in spleen and lymph nodes • Constantly amplifying

50. Attack… • Cell Mediated Immune Response • Antibody Mediated Immune Response