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Toxins and Evasins (How can your own immune respnse kill you? (Viral…

- - - - recruit neutrophils
        
        they can cause damage to cells near by
    - - Meningitis
  - - - induced by prior infection
      - E.g.
        
        streptococcus
        
        Mechanism
        
        Antibodies made against M protein
        
        or Complement Casscade bring neutrophils
        
        After bacteria killed, Ab circulate in blood strem
        
        Happens to be protein in heart like M protein
        
        Damage Heart
        
        Immune mimicry
  - - - produce IFN (interferon)
      - Therefore virus produce IFN repressors
    - - tumor supressor genes activate
        
        p53
        
        kill viral genes
      - therefore, virus makes p53 inhibitors
        
        e6 protein
        
        HPV
    - - want to be taken up into to cell more readily
        
        Coat themselves with LPS & PG from native flora
    - - Viral proteins not displayed on surface of APC
        
        Cytotoxic T cell cannot find them
    - - produce MHC1 analog
        
        Looks like MHC1 but doesn't display antigens
        
        Makes NK cells think everything is fine
    - - Bac usually spread cell-cell w/ actin filaments
        
        dodge antibodies & complement
        
        AKA serum immune proteins
      - Virus do similar thing
        
        Enter through cell membrane fusion
        
        Why virus have envelope?
        
        Not helpful
        
        Budding virus
        
        Can fuse with nearby cell using membrane fusion
      - =fused cells
  - - - aflatoxin
      - ergot posoning
    - - invade superficial skin
      - makes skin hard
    - - inhaling spores
      - enter mold form in lungs
        
        transform to yeast form in body
  - - - RBC
        
        dont have MHC1
        
        not exposed to humoral immunity
- - - - Lipid A Part
        
        Has 2 weird features
        
        Dissaccharide diphosphate backbone
        
        Instead of glycerol
        
        Branched FA
        
        Not tyically there
        
        Body recog as foreign
      - O polysaccaride
        
        Also called O-antigen
        
        Highly antigenic
      - Core polysaccaride
      - Injection into patient must be LPS free
        
        pyrogen free
        
        How detect LPS in soln?
        
        Limulus amoebocyte assay
        
        Ameobocyte= Horseshoe Crabs
        
        In precense of LPS
        
        Coagulate
        
        New test put soln in lipid
        
        analyzed with light
        
        shows a pattern distinct to LPS
      - Heat stable
        
        Difficult to make a endotoxin vaccine
  - - - Complex bind to
        
        Macrophage
        
        CD14
        
        TLR4
    - - LPS after binding to macrp[hage
        
        release signals to multiple inflammosomes
        
        secretion of cytokines
        
        increased capilary perm
        
        diapedisis
        
        If over released
        
        septic shock
        
        PRR recog PAMP
        
        PRR=Pattern recognition receptor
        
        PAMP=Pathogen Associated Molecular Pattern
  - - - Bacteria cant give ability to others
- - - - A-B type
      - Not heat stable
        
        Easy to make a toxoid vaccine
        
        Easily denatured
  - - - interfere with mechanism w/in the cell
      - A-B toxins
        
        Structure
        
        A part
        
        toxic effect
        
        Active
        
        B part
        
        Binding
        
        Bind to receptors
        
        Receptor on host cell
        
        Not themselves toxic
        
        Protective antigen
        
        can be used to make a protective vaccine
        
        protect us vs toxin
        
        Mechanism
        
        1.binding
        
        2.Uptake of A part
        
        Endosome
        
        Pore complex
        
        A part activated
        
        Functions
        
        Inhibit Protein Syntheis
        
        Interfere with ribosome
        
        Interfere with transcription factors
        
        Incr cAMP
        
        incr fluid secretion
        
        Pneumonia
        
        Diarreha
        
        Swelling
        
        Inhibit cell-cell communication
        
        Failure leads to apoptosis
        
        Body thinks they are cancer cells
        
        Example
        
        Anthrax toxin
        
        A2B
    - - hemolysins
        
        Alpha
        
        pore complex
        
        Beta
        
        phospholipase
        
        remove head group of phospholipids
        
        Gamma
    - - exfoliative toxin
        
        peel off outer layer skins
        
        damages desmolein
        
        cellular glue that connect cells
      - hyaluronidase
        
        destroy connective tissue between cells
        
        destroy hyaluronic acid
    - - Superantigen toxin
        
        Over-activate immune system
        
        Mechanism
        
        1.APC display antigen
        
        What if antigen wasnt being presented?
        
        T cell receptor cant recognize antigen
        
        Leads to way too much inflammation since all APC are being "recognized" with antigen
        
        1 more item...
        
        Superantigen
        
        Covalently crosslink MHC 2 with TCR
        
        T cell receptor recog antigen
        
        Activate phosphorelay signal
        
        Activate T helper cell