BIO SG - Final

BIO SG - Final - BIO SG FINAL LECTURE 19 THE IMMUNE SYSTEM...

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BIO SG – FINAL LECTURE 19 – THE IMMUNE SYSTEM o Pathogens Disease producers Includes: viruses, bacteria, eukaryotic parasites Immune system must determine self from non-self o Must be lethal to foreign objects o Benign to the native 2 kinds of immunity o Innate (natural) Provides immediate defense Non-specific resistance to pathogens Depends on: low pH of stomach/vagina low concentration of iron in body fluids/tissues phagocytosis inflammation Part of signaling network We have at least 8 Toll-like proteins o Sense infection by responding to chemicals that are unique to pathogens DNA sequences Bacterial cell walls Liposaccharides of outer membrane of gram negative bacteria o Adaptive (acquired) Takes time, but has memory  Allows for quick response to subsequent infections by same pathogen Depends on response to antigens Molecule – usually protein Two categories: Humoral (depends on activity of blood proteins) Cellular (depends on responses of cells) Has appearance of “learning” Cells o Produced continuously by differentiation of stem cells in the bone marrow Most become RBCs Some become phagocytes or lymphocytes o Some lymphocytes travel to the thymus Organ of lymphatic system o Lymphocytes in the thymus differentiate into various classes of T cells T helper cells Use CD4 receptors to probe MHC II of macrophages/dendritic cells If peptide of antigen is detected @ the same time another signal is received indicating infection, T- cell is aroused o Causes T cell to divide several times o Then secretes signal molecules that are peptides called interleukins One stimulates other T cells to divide Another stimulates B cells to divide rapidly if they sense an antigen T killer cells Have receptor called CD8 that probes MHC 1
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If peptide from foreign protein (cancer cell or virus) is detected, displaying cell is killed o Can mistakenly damage healthy normal cells o Other lymphocytes mature in the bone marrow then travel to lymph nodes or spleen Above kidneys, behind the stomach Once matured, these become B cells
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This note was uploaded on 04/14/2008 for the course BIS 10 taught by Professor A.marr during the Winter '07 term at UC Davis.

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BIO SG - Final - BIO SG FINAL LECTURE 19 THE IMMUNE SYSTEM...

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