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B Cells and Immunity

B Cells and Immunity. Figure 20–22 The Primary and Secondary Responses in Antibody-Mediated Immunity. B Cells and Immunity. Effects of Memory B Cell Activation IgG Rises very high and very quickly Can remain elevated for extended time IgM Production is also quicker Slightly extended.

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B Cells and Immunity

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  1. B Cells and Immunity Figure 20–22 The Primary and Secondary Responses in Antibody-Mediated Immunity.

  2. B Cells and Immunity • Effects of Memory B Cell Activation • IgG • Rises very high and very quickly • Can remain elevated for extended time • IgM • Production is also quicker • Slightly extended

  3. B Cells and Immunity • Combined Responses to Bacterial Infection • Neutrophils and NK cells begin killing bacteria • Cytokines draw phagocytes to area • Antigen presentation activates • Helper T cells • Cytotoxic T cells • B cells activate and differentiate • Plasma cells increase antibody levels

  4. B Cells and Immunity Figure 20–24 The Course of the Body’s Response to a Bacterial Infection.

  5. B Cells and Immunity • Combined Responses to Viral Infection • Similar to bacterial infection • But cytotoxic T cells and NK cells are activated by contact with virus-infected cells

  6. B Cells and Immunity Figure 20–25 Defenses against Bacterial and Viral Pathogens.

  7. B Cells and Immunity Figure 20–25 Defenses against Bacterial and Viral Pathogens.

  8. B Cells and Immunity Figure 20–23 An Integrated Summary of the Immune Response.

  9. B Cells and Immunity

  10. B Cells and Immunity

  11. Immune System Development • Immune System Development • Fetus can produce immune response (has immunological competence) • After exposure to antigen • At about 3–4 months

  12. Immune System Development • Development of Immunological Competence • Fetal thymus cells migrate to tissues that form T cells • Liver and bone marrow produce B cells • 4-month fetus produces IgM antibodies

  13. Immune System Development • Before Birth • Maternal IgG antibodies • Pass through placenta • Provide passive immunity to fetus • After Birth • Mother’s milk provides IgA antibodies • While passive immunity is lost

  14. Immune System Development • Normal Resistance • Infant produces IgG antibodies through exposure to antigens • Antibody, B cell, and T cell levels slowly rise to adult levels • About age 12

  15. Immune System Development • Six Groups of Hormonal Cytokines • Interleukins • Interferons • Tumor necrosis factors (TNFs) • Chemicals that regulate phagocytic activities • Colony-stimulating factors (CSFs) • Miscellaneous cytokines

  16. Immune System Development

  17. Immune System Development

  18. Immune System Development • Immune Disorders • Autoimmune disorders • Immunodeficiency disease • Allergies

  19. Immune System Development • Autoimmune Disorders • A malfunction of system that recognizes and ignores “normal” antigens • Activated B cells make autoantibodies against body cells • Thyroiditis • Rheumatoid arthritis • Insulin-dependent diabetes mellitus (IDDM)

  20. Immune System Development • Immunodeficiency diseases result from • Problems with embryological development of lymphoid tissues: • Can result in severe combined immunodeficiency disease (SCID) • Viral infections such as HIV • Can result in AIDS • Immunosuppressive drugs or radiation treatments: • Can lead to complete immunological failure

  21. Immune System Development • Allergies • Inappropriate or excessive immune responses to antigens • Allergens • Antigens that trigger allergic reactions

  22. Immune System Development • Four Categories of Allergic Reactions • Type I • Immediate hypersensitivity • Type II • Cytotoxic reactions • Type III • Immune complex disorders • Type IV • Delayed hypersensitivity

  23. Immune System Development • Type I Allergy • Also called immediate hypersensitivity • A rapid and severe response to the presence of an antigen • Most commonly recognized type of allergy • Includes allergic rhinitis (environmental allergies)

  24. Immune System Development • Type I Allergy • Sensitization leads to • Production of large quantities of IgE antibodies distributed throughout the body • Second exposure leads to • Massive inflammation of affected tissues

  25. Immune System Development • Type I Allergy • Severity of reaction depends on • Individual sensitivity • Locations involved • Allergens (antigens that trigger reaction) in bloodstream may cause anaphylaxis

  26. Immune System Development • Anaphylaxis • Can be fatal • Affects cells throughout body • Changes capillary permeability • Produce swelling (hives) on skin • Smooth muscles of respiratory system contract • Make breathing difficult • Peripheral vasodilatation • Can cause circulatory collapse (anaphylactic shock)

  27. Immune System Development Figure 20–26 The Mechanism of Anaphylaxis.

  28. Immune System Development • Antihistamines • Drugs that block histamine released by mast cells • Can relieve mild symptoms of immediate hypersensitivity

  29. Immune System Development • Stress and the Immune Response • Glucocorticoids • Secreted to limit immune response • Long-term secretion (chronic stress): • inhibits immune response • lowers resistance to disease

  30. Immune System Development • Functions of Glucocorticoids • Depression of the inflammatory response • Reduction in abundance and activity of phagocytes • Inhibition of interleukin secretion

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