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A Brief Overview of Immunology. Dennis E. Lopatin, Ph.D. University of Michigan. What’s the bottom line?. Immune system recognizes foreign agents Immune response is mounted to produce activated T cells and specific antibodies Antibodies react with foreign agent
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A Brief Overview of Immunology Dennis E. Lopatin, Ph.D. University of Michigan
What’s the bottom line? • Immune system recognizes foreign agents • Immune response is mounted to produce activated T cells and specific antibodies • Antibodies react with foreign agent • Activated T cells react with foreign agent • Activated T cells may influence other cells • Antibodies provide specificity to non-specific cytotoxic systems • Immune system “remembers: what it did.
What happens upon antigen exposure? B lymphocytes T lymphocytes Virgin lymphocyte pool PRIMARY RESPONSE effector cells memory cell pool SECONDARY RESPONSE Exposure to Antigen (Naturally-acquired or artificial) effector cells memory cell pool Regulatory Cytotoxic Activated T lymphocytes Plasma cells Antibodies
Where is that stuff? Blood Serum or Plasma Leukocytes, Platelets and RBC Mononuclear Cells Polymorphonuclear leukocytes (or Granulocytes) Serum Proteins • Immunoglobulins • Complement • Clotting factors • Many others • Lymphocytes (T cells, B cells & NK cells) • Monocytes • Neutrophils • Eosinophils • Basophils
What are the effector functions? Antibody-Mediated Ways to Destroy the Target • Complement activation • Agglutination • Neutralization • Mask receptors • Antibody-mediated cellular cytotoxicity (ADCC) • Opsonization and phagocytosis Cell-Mediated • Cytotoxic T-Lymphocyte • Natural Killer Cells • Antibody-mediated cellular cytotoxicity (ADCC)
When a good response goes terribly bad Hypersensitivity Reactions • Reactions that are detrimental to the host • The result of autoimmunity • An atypical immune response • An inability to eliminate a pathogen • The tissues become a carrier for a hapten • Transplanted tissues are recognized