The Immune System

1. The Immune System By Rebecca Ast, Corey Forman, & Sydney Saltzman

2. Nonspecific and Specific Immunity Sydney Saltzman

3. Nonspecific Specific Immune System Third Line of Defense Lymphocytes Antibodies • Do not distinguish between pathogens • First Line of Defense • Barriers • Second Line of Defense • Phagocytosis • The Inflammatory Response • Antimicrobial proteins The Body’s Defenses

4. Does not distinguish between infectious agents • Same response regardless of pathogen • Consists of: • First Line of Defense • Skin and mucous membranes • Secretions of these membranes • Second Line of Defense • Phagocytic white blood cells • Inflammatory response • Antimicrobial proteins Non Specific Defense

5. Blocks pathogens from entering body • Skin • Saliva, tears, mucous • Wash away pathogens • Contain antimicrobial proteins • Lysozyme • Sweat • PH from 3 to5 • Prevents growth of microbes • Mucus • Prevents pathogens from entering organs First Line of Defense

6. Pathogens that get past first line of defense • Phagocytosis • Ingestion of microbes/ pathogens • 4 types of phagocytic white blood cells • Followed by inflammatory response • Goal: Stop spread of pathogens before specific immune responses begin Second Line of Defense

7. Neutrophils • 60%-70% of WBC’s • Attracted by Chemical signals • Ingest microbes and self destruct • Monocytes • 5% of WBC’s • Develop into macrophages • Eosinophils • 1.5% of WBC’s • Discharge toxic enzymes • Phagocytosis limited • Macrophages • Largest and most effective • Long lasting • Pseudopodia engulf pathogen • Can destroy it 2 ways: • Digest microbe • lysozyme • Antimicrobial Protein • Toxic oxygen • Superoxide anion • Nitric oxide Phagocytic White Blood Cells

8. Macrophages migrate throughout body • Some permanent in lung, liver, kidney, brain, lymph nodes, spleen, connective tissue • Good for fighting pathogens • NaturalKiller Cells • Destroy body cells infected with a virus/ cancer cells • Attack the cell’s membrane • Lyse Second Line of Defense (Cont.)

9. Open Injury, entry of microbes • Capillaries constrict/dilate • Increased blood flow to area • Causes redness/heat • Capillaries leak fluid • Swelling • Triggered by Chemical Signals • From pathogen • Or Body cells • Histamine The Inflammatory Response

10. Histamine • Produced by certain leukocytes • Causes dilation, increased permeability of capillaries • Increased blood flow to injury • Speeds blood clotting/ recovery • Allows phagocyte cells to reach injury • Chemokins • Released by endothelial cells/monocytes • Attract phagocytes • Once Phagocytes Arrive… • Neutrophils ingest/ self destruct • Macrophages ingest pathogens, clean up damage The Inflammatory Response

11. Severe Injury or infection • Injured cells call for release of extra neutrophils from bone marrow • Number of WBC’s in blood increases drastically • Pyrogens • Released by leukocytes • Raise body’s temperature to reduce growth of pathogens • Speeds up phagocytosis/ tissue repair • Septic Shock • Inflammatory response overwhelms the body • High fever, low blood pressure • #1 COD in US intensive care units Extreme Immune Response

12. Complement system • 20 proteins • Attract phagocyte cells to infection • Interferons • Secreted by cells infected with viruses • Causes neighbors to produce chemicals inhibiting viral reproduction • Reduce spread of viruses between cells Antimicrobial Proteins

13. Lymphocytes • B cells • T cells • Primary Immune Response • Secondary Immune Response • Self tolerance • Major Histocompatibility Complex Specific Immunity

14. Key components of specific immunity • Type of WBC • Found in spleen, lymph nodes, other tissues • Two types: • T lymphocytes • B lymphocytes • Recognize and respond to specific microbes • Respond to Antigens • Pathogen molecules on surface • Antigen receptors • On lymphocyte plasma membrane • Help recognizes specific antigens Lymphocytes

15. B cells • Produce antibodies • Proteins • Help identify pathogens • Antigen receptors • Membrane antibodies • T cells • Just as specific as B cells • Never produced in secreted form • Lymphocytes have 100,000 antigen receptors • All specific • Specific receptors determined early in development • Genetic recombination of antibody genes and receptor genes • Immune system can respond to millions of antigens Antigen Receptors

16. Antigens react with lymphocytes with their specific antigen receptor • Contact between lymphocyte and antigen activates lymphocyte • Lymphocyte divides • Effector cells • Fight the same antigen • Memory cells • Long lasting • Have antigen receptors for specific antigen • Clonal selection Antigen/ Lymphocyte Interactions

17. Primary immune response • First time body is exposed to antigen • 10-17 days • Produce plasma cells • Effector B cells that produce antibodies • Person may become sick • Secondary immune response • Body exposed to antigen again • 2 to 7 days • Produces more antibodies/ more effective antibodies • Immunological memory Immune Responses

18. Lymphocytes originate in bone marrow • T cells mature in Thymus • B cells remain in bone marrow • During maturation antigen receptors tested • Cells with receptors for body cells destroyed • Self tolerance is critical • Autoimmune disease • Multiple Sclerosis Self from Nonself

19. Family of genes encoding for cell surface glycoproteins • Mark body molecules as self • Two classes: • Class I MHC • Found on most body cells • Class II MHC • Macrophages, B cells, certain T cell, thymus • Antigen presenting cells • Large # of MHC genes • Each individual has unique set of MHC molecules • Biochemical fingerprint • Responsible for transplant rejections Major Histocompatibility Complex

20. Diversity of MHC molecules increases likelihood of survival in epidemic • MHC molecules presents an antigen inside a cell to a T-cell • 2 types of T cells: • Cytoxic T cells • Respond to MHC I molecules • Kill infected cells • Helper T cells • Respond to MHC II molecules • Signal for other cells to fight pathogen T Cells

21. Immune Responses Corey Forman

22. Infection in blood and body tissues • Phagocytosis and phagocytes • Helper T cells-Activation phase • Produce cytokines for B cells • Plasma cells or B memory cells Humoral Immunity

23. Cytotoxic T cells • Recognize foreign material and produce T memory cells Cell-Mediated Immunity

25. CD4 and CD8

26. Antibodies

27. Culture in a lab • Produced by a single B cell clone • All specific for same epitope • Used to tag antigens Monoclonal Antibodies

28. Opsonization Agglutination

29. Immunity in Health and Disease Rebecca Ast

30. Active Immunity Passive Immunity Passive immunity is when antibodies are transferred from one individual to another Naturally acquired passive immunity occurs during pregnancy Artificially acquired is a short-term immunization by the injection of antibodies • Active immunity is when the immune system depends on the response of the infected person’s own immune system • Naturally acquired • Occurs when the person is exposed to a live pathogen • Vaccines

31. Rh Factor A and B antigens Elicits IgM anti-blood-group antibodies Induce T-independent responses Primary response Does not cross placenta If somebody gets a blood transfusion that is type A and receives type B blood causes clumping which can be deadly. • Elicits IgG anti-blood-group antibodies • Can cross placenta • If an Rh- individual is given Rh+ blood, the receiver will reject the blood • Anti-Rh produce • After enough is made, starts to coat the Rh+ red blood cells Immune Responses

32. If a woman who is Rh negative and a man who is Rh positive conceive a baby, there is the potential for a baby to have a health problem • Baby growing inside the Rh-negative mother may have Rh-positive blood’ • Not a problem for first pregnancy, unless there's some sort of abnormality, the fetus's blood does not normally enter the mother's circulatory • If baby and mother’s blood intermingle then that’s when the problem arises • The mother's body recognizes the Rh protein as a foreign substance and can begin producing antibodies • Destroys baby’s blood Rh Incompatibility Between Mother and Fetus

33. The mother is injected with anti Rh bodies after delivering first Rh-positive baby • is passively immunized to eliminate Rh antigen before her own response system responds and generates. Precautionary Measures

34. Attempts are made to match the MHC of the tissue donor and recipient as closely as possible. • Usually siblings are the closest matches • In addition to a close match, various medicines are necessary to suppress the immune response to the transplant. • In bone marrow transplants it’s the same as the other transplant • However, the recipient is typically treated with irradiation to eliminate his or her own marrow cells. • This leaves little chance to graft rejection How To Reduce the Risks of Tissue Transplants

35. When the plasma cells secrete IgE specific for pollen allergies. • Some of the IgE antibodies attach by their tails to mast cells present in connective tissues. • Later, when pollen grains enter the body, they attach to the antigen-binding sites of mast cell-associated IgEcrosslinking, adjacent antibody molecules. • This event induces the mast cell to degranulate- That is to release histamine and other inflammatory agents from vesicles called granules. • Histamines cause dilation and increased permeability of small blood cells. • These inflammatory events lead to typical allergy symptoms. Allergic Reactions

36. Occurs when widespread mast cell degradnulation triggers abrupt dilation of peripheral blood vessels • Causing precipitous drop in blood pressure. • People with severe hypersensitivities carry syringes containing the hormone epiphrine • Which counteracts this allergic response. Anaphylactic Shock

37. Systemic lupus erythematosus • Rheumatoid arthritis • Insulin-dependent diabetes mellitus • Mechanisms that lead to autoimmunity are not fully understood. • Autoimmune disease likely arises from some failure in immune regulations. • Once thought it was self-reactive lymph nodes, not true because even healthy individuals have self-reacting lymph nodes. • One intriguing finding is that the inheritance of particular MHC alleles is associated with susceptibility to certain autoimmune diseases. Autoimmune Disorders

38. Many inborn deficiencies affect the function of either humoral or cell mediated immune defenses. • Inborn is when you are born with the autoimmune deficiency. • Acquired is when the problem is developed over time. Inborn and Acquired Immunodeficiency

39. A retrovirus called human immunodeficiency virus (HIV) causes AIDS. • Two strains HIV-1 and HIV-2 • HIV-1 is the more widespread strains that are more virulent. • Both strains infect cells that bear surface CD4 molecules • CD4 cells are located on help T cells and enhance the binding between those cells and class 11 MHC-bearing antigen-presenting cells. • Entry of virus requires CD4 on surface of susceptible cell and second protein molecule, a coreptor. HIV

40. Its incidence throughout the world is that is it rapidly spreading and killing millions. • Millions have been infected • HIV is transmitted through blood or any other bodily fluids. • It is spread through contact and intercourse. • Strategies that can reduce a person’s risk of infection is • to use protection during intercourse • making sure you do not transfer any blood or other fluids to yourself. How HIV is Transmitted