Immunology Lecture Notes 2024-2025 PDF

Academic Year: 2024 / 2025 Introduction to Immunology  Acquired Immunity 3rd Line of Defense B Cells and T H Cells Antibodies AQUIRED (ACTIVE) IMMUNITY § Specific defense u lymphocytes § B lymphocytes (B cells) § T lymphoc...

Academic Year: 2024 / 2025 Introduction to Immunology  Acquired Immunity 3rd Line of Defense B Cells and T H Cells Antibodies AQUIRED (ACTIVE) IMMUNITY § Specific defense u lymphocytes § B lymphocytes (B cells) § T lymphocytes (T cells) u antibodies § immunoglobulins § Responds to… u antigens § specific pathogens § specific toxins § abnormal body cells (cancer)  How are invaders recognized: antigens § Antigens u proteins that serve as cellular name tags § foreign antigens cause response from WBCs w viruses, bacteria, protozoa, parasitic worms, fungi, toxins w non-pathogens: pollen & transplanted tissue § B cells & T cells respond to different antigens u B cells recognize intact antigens § pathogens in blood & lymph u T cells recognize antigen fragments § pathogens which have already infected cells “self” “foreign”  bone marrow Lymphocytes § B cells u mature in bone marrow u humoral response system § “humors” = body fluids § produce antibodies § T cells u mature in thymus u cellular response system § Learn to distinguish “self” from “non-self” antigens during maturation u if they react to “self” antigens, they are destroyed during maturation LET’S TALK ABOUT THE B CELLS  B cells!!!!!! § Humoral response = “in fluid” u defense against attackers circulating freely in blood & lymph § Specific response u produce a specific antibody against a specific antigen § Types of B cells § plasma cells w immediate production of antibodies w rapid response, short term release § memory cells w long term immunity  Y Y Y Y YY Y Y Antibodies YY YY Y Y Y YY Y Y Y Y Y § Proteins that bind to a specific antigen Y Y YY Y YY Y multi-chain proteins produced by B cells Y u Y Y u binding region matches molecular shape of antigens u each antibody is unique & specific Y YY Y § millions of antibodies respond to millions of foreign YY antigens Y Y u tagging “handcuffs” antigen- antigen Y § “this is foreign…gotcha!” binding site Y on antibody Y Y variable Y binding region Y each B cell has ~100,000 antigen receptors  invading Exposure pathogens to tagged with Classes of antibodies antigen antibodies IgM IgG Antibody levels Y macrophage § Immunoglobulins (aka antibody) Y Y eating tagged Y IgM invaders Y u § 1st immune response Y § activate complement proteins 0 2 Weeks 4 6 u IgG § 2nd response, major antibody circulating in plasma § promote phagocytosis by macrophages u IgA § in external secretions, sweat & mother’s milk u IgE § promote release of histamine & lots of bodily fluids § evolved as reaction to parasites § triggers allergic reaction u IgD § present on surface of Beta cells that have not been exposed to antigens  10 to 17 days for full response B cell immune response Y Y YY YY Y Y YY YY tested by Y Y Y Y Y Y Y YY Y B cells YY Y YY YY YY Y (in blood & lymph) YY Y invader Y Y Y Y Y (foreign antigen) B cells + antibodies Y Y memory cells Y Y YY Y Y Y “reserves” Y Y YY Y Y YY Y Y Y Y Y Y captured recognition YY Y Y Y Y Y YY YY invaders Y Y Y YY Y Y Y Y Y Y Y YY Y Y Y Y Y Y Y YYYY Y Y Y Y Y Y Y YY YY Y Y Y YY Y Y Y Y Y Y Y Y Y Y Y YY Y Y Y Y Y Y Y Y Y Y Y Y Y Y clone Y Y Y YY Y Y Y YY YY 1000s of plasma plasma cells Y cells Y Y Y Y Y Y Y Y Y release antibodies 1° vs 2° response to disease § Memory B cells allow a rapid, amplified response with future exposure to pathogen How do vertebrates produce millions of antibody proteins, if they only have a few hundred genes coding antibody for those proteins? By DNA rearrangement NA & somatic mutation of m R lat ion vertebrates can Tr a n s rearrangement produce millions of of DNA mRNA V B & T cells of g e ne tion ns crip Tra D DNA of differentiated B cell J C C B cell chromosome of undifferentiated B cell  Vaccinations § Immune system exposed to harmless version of pathogen u triggers active immunity u stimulates immune system to produce antibodies to invader u rapid response if future exposure § Most successful against viral diseases Jonas Salk 1914 – 1995 § Developed first vaccineApril 12, 1955 § against polio ,attacks motor neurons  PASSIVE IMMUNITY § Obtaining antibodies from another individual § Maternal immunity u antibodies pass from mother to baby across placenta or in mother’s milk u critical role of breastfeeding in infant health § mother is creating antibodies against pathogens baby is being exposed to § Injection u injection of antibodies u short-term immunity  Helpful Advice Work in a group An effective study group means: Schedule meetings Pre-arranged assignments Ideally 3 – 4 members Analyze Keep in mind two related but distinct course goals: Implement Success on exams Long-term understanding Test Develop Conceive