1. Immune System Chapter 43

3. Introduction to the Immune System The human body must defend itself against unwelcome intruders. The human body must defend itself against unwelcome intruders. It must also deal with abnormal body cells, which, in some cases, may develop into cancer. It must also deal with abnormal body cells, which, in some cases, may develop into cancer. Two major kinds of defense have evolved to counter such threats. Two major kinds of defense have evolved to counter such threats. Innate Defenses Innate Defenses Acquired Defenses Acquired Defenses

4. Overview of the Immune System

6. External Barriers: intact skin epidermis intact skin epidermis Acid mantle of skin Acid mantle of skin Keratin Keratin Intact mucous membranes Intact mucous membranes Mucus Mucus Nasal hairs Nasal hairs Cilia Cilia Gastric juice Gastric juice Acid mantle of vagina Acid mantle of vagina Lacrimal secretion Lacrimal secretion Urine Urine Oil (sebum) secretions Oil (sebum) secretions

7. Internal Cellular Defenses: Phagocytic cells Phagocytic cells Neutrophils Neutrophils Monocytes Monocytes Eosinophils Eosinophils Dendritic cells Dendritic cells

8. Internal Cellular Defenses

9. Phagocytic Responses Pseudopodia Pseudopodia Ingestion Ingestion Vacuole Vacuole Fuse with lysosome Fuse with lysosome Digestion Digestion Exocytosis Exocytosis

11. Internal Cellular Defenses: Natural Killer Cells Natural Killer Cells Non-specific Non-specific Perforins Perforins Apoptosis Apoptosis

12. Natural Killer (NK) Cells (Cytotoxic lymphocyte) Natural Killer (NK) Cells (Cytotoxic lymphocyte) Promote cells lysis by direct cell attack against virus-infected or cancerous body cells Promote cells lysis by direct cell attack against virus-infected or cancerous body cells Referred to as null third population cells that are spontaneous non antigen recognizing. Referred to as null third population cells that are spontaneous non antigen recognizing. Lack surface antigen receptors but recognize certain surface sugars on infected or cancerous cells Lack surface antigen receptors but recognize certain surface sugars on infected or cancerous cells Release cytolytic chemicals (perforins) that attack a targets cell's cell membrane and bore hole. Granzymes are released and cellular enzymes disrupted. Release cytolytic chemicals (perforins) that attack a targets cell's cell membrane and bore hole. Granzymes are released and cellular enzymes disrupted. Present in spleen, lymph nodes, red bone marrow, and blood Present in spleen, lymph nodes, red bone marrow, and blood

13. Inflammatory Response

16. Cardinal signs of inflammation Cardinal signs of inflammation redness, pain, heat and swelling Local versus systemic inflammation Local versus systemic inflammation Septic shock Septic shock

17. Interferons - proteins that diffuse to nearby cells, where they stimulate the synthesis of a protein known as PKE, which then interferes with viral replication in those cells by blocking protein synthesis at the ribosomes Interferons - proteins that diffuse to nearby cells, where they stimulate the synthesis of a protein known as PKE, which then interferes with viral replication in those cells by blocking protein synthesis at the ribosomes Gamma interferon - produced by lymphocytes, mobilizes and activates macrophages and NK cells, stimulates synthesis and expression of more class I and II MHC, and enhances activity of B cells and cytotoxic T cells Gamma interferon - produced by lymphocytes, mobilizes and activates macrophages and NK cells, stimulates synthesis and expression of more class I and II MHC, and enhances activity of B cells and cytotoxic T cells Alpha interferon - produced by most leukocytes, mobilizes and activates macrophages and NK cells Alpha interferon - produced by most leukocytes, mobilizes and activates macrophages and NK cells Beta interferon - produced by fibroblasts, mobilizes and activates macrophages and acts to reduce inflammation Beta interferon - produced by fibroblasts, mobilizes and activates macrophages and acts to reduce inflammation

19. Complement - twenty plasma proteins that amplify the inflammatory response, lyses microorganisms and enhances phagocytosis by opsonization. Two pathways: classic and alternative. Complement - twenty plasma proteins that amplify the inflammatory response, lyses microorganisms and enhances phagocytosis by opsonization. Two pathways: classic and alternative. Pyrogens - secreted by macrophages and signal the body to increase temperature; high body temperature inhibits microbial multiplication and enhances body repair processes. Pyrogens - secreted by macrophages and signal the body to increase temperature; high body temperature inhibits microbial multiplication and enhances body repair processes.

20. Antigen (Ags) Antigens are substances that can mobilize immune system and provoke a response Antigens are substances that can mobilize immune system and provoke a response Are considered nonself Are considered nonself ii. Nonself Antigens ii. Nonself Antigens Types: Types: Complete antigen - functional properties: Complete antigen - functional properties: immunogenecity - stimulate B and T cell formation and antibody production immunogenecity - stimulate B and T cell formation and antibody production reactivity - react with B and T cells reactivity - react with B and T cells

21. Small antigens (peptide, nucleotide, hormones) - may bind to body's own biological molecules (proteins); antigen when bound to body's own molecules may cause an immune response, this is called an allergy. Small antigens are called haptens (incomplete antigen) and alone are not immunogenic. Small antigens (peptide, nucleotide, hormones) - may bind to body's own biological molecules (proteins); antigen when bound to body's own molecules may cause an immune response, this is called an allergy. Small antigens are called haptens (incomplete antigen) and alone are not immunogenic. Reactivity (immune response) is dependent upon antigen structure; localized regions, antigenic determinants are where antibodies or B and T lymphocytes can bind. Reactivity (immune response) is dependent upon antigen structure; localized regions, antigenic determinants are where antibodies or B and T lymphocytes can bind. iii. Self Antigens iii. Self Antigens Are not foreign or antigenic to us, but are strongly antigenic to other individuals Are not foreign or antigenic to us, but are strongly antigenic to other individuals egs. blood transfusions and organ transplants egs. blood transfusions and organ transplants

23. Major Histocompatibility Complex (MHC) antigens Found on all cells except RBCs Major Histocompatibility Complex (MHC) antigens Found on all cells except RBCs Involved in tissue recognition (aids in transplantation recognition) Involved in tissue recognition (aids in transplantation recognition) Two types of MHC antigens: MHC class I found on all body cells Two types of MHC antigens: MHC class I found on all body cells MHC class II found on antigen present cells MHC class II found on antigen present cells Antigen Presentation Ingestion of the antigen Antigen Presentation Ingestion of the antigen Digestion of antigen into peptide fragments Digestion of antigen into peptide fragments Fusion of vesicles (peptide fragments with MHC-II molecules) Fusion of vesicles (peptide fragments with MHC-II molecules) Binding of peptide fragments to MHC-II molecules Binding of peptide fragments to MHC-II molecules Insertion of antigen-MHC-II complex into plasma membrane Insertion of antigen-MHC-II complex into plasma membrane

25. ACQUIRED IMMUNITY All cells have cell surface macromolecules All cells have cell surface macromolecules Adaptive immunity is sensitive to specific infections Adaptive immunity is sensitive to specific infections Antigens distinguish self versus non-self Antigens distinguish self versus non-self

26. ACQUIRED IMMUNITY

28. Humoral Immunity Also known as antibody-mediated immunity Also known as antibody-mediated immunity Utilizes B-lymphocytes Utilizes B-lymphocytes Recognizes antigen directly Recognizes antigen directly Made in the bone marrow Made in the bone marrow

30. Clonal Selection and Proliferation

31. Antibody Structure

32. Antibody Classes

34. Antibody Functions

35. Cell-Mediated Immunity Utilizes T-lymphocytes Utilizes T-lymphocytes T-cells are made in the bone marrow but mature in the thymus gland. T-cells are made in the bone marrow but mature in the thymus gland. Cannot recognize antigens directly Cannot recognize antigens directly

36. Cell-Mediated Immunity CLASS I MHC PROTEINCLASS II MHC PROTEIN

37. Helper T-Lymphocyte Stimulation

38. Helper T-cells stimulate B-cells

39. Cytotoxic T-Lymphocyte Stimulation

40. Overview of Adaptive Immunity

41. Adaptive Immunity

42. Problems with the Immune System Blood Transfusion Reaction Blood Transfusion Reaction Tissue Rejection Tissue Rejection Allergies Allergies Autoimmune disease Autoimmune disease Immunodeficiencies Immunodeficiencies

43. Blood Transfusion Reactions

44. Rhesus Factor Blood Type Presence of D Antigen? Type of Antibody? Receive? Rh Positive YesNone + and - Rh Negative NoAnti-D - only

45. Tissue Transplant and Rejection Autograft Autograft Isograft Isograft Allograft Allograft Xenograft Xenograft

46. Allergies or Hypersensitivities Type I Type I Type II Type II Type III Type III Type IV Type IV

47. Autoimmune Diseases Multiple sclerosis Multiple sclerosis Rheumatoid arthritis Rheumatoid arthritis Systemic lupus Systemic lupus Grave's disease Grave's disease Type I diabetes mellitus Type I diabetes mellitus

48. Immunodeficiency Diseases Primary Immunodeficiency Primary Immunodeficiency a.k.a. “inborn” a.k.a. “inborn” SCID SCID Secondary Immunodeficiency Secondary Immunodeficiency a.k.a. “acquired” a.k.a. “acquired” Drugs Drugs Stress and Hodgkin’s Stress and Hodgkin’s AIDS AIDS