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46 Cards in this Set
- Front
- Back
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Review--> Non-specific defense mechanisms |
Neutrophils and Macrophages --> phagocytosis Macrophages--> cytokines --> stimulate inflammation inflammation= warmth, swelling, redness, pain |
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Complement and the Membrane Attack Complex! |
forms pores in the pathogens Oploninze surface of pathogen |
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Natural Killers--> |
protect against virus infected cells |
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Acquired/adaptive immunity |
Specific resistance to certain pathogens (antigens) |
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Discriminates--> |
foreignness (danger) Slow starting --> need nonspecific defenses to be engaged |
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Immune memory-->
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faster response on repeat exposure |
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Antigens and Antibodies: Antigens---> |
ANYTHING that stimulates an immune response --usually proteins or peptides --forgein -----autoimmune disorders |
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Antibodies--> |
"Y-shaped proteins on the surface of B cells that is secreted into the blood or lymph in response to an antigenic stimulus." *** Host proteins that bind specifically to antigens ** Antibodies (Ab) bind antigens specifically |
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Each antigen has many --> |
epitopes --antibody binding sites ** antibodies bind to epitopes ON an antigen ** different epitopes; locationally where antibody binds |
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Where do antibodies come from? |
B CELLS ** which are generated in bone marrow 88 As a B cell differentiates, gene segments are randomly selected and combined to encode a UNIQUE V REGION ( spontaneous recombination) |
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Immature B cells that bind "self" molecules die by.... |
apoptosis ** this ensures lots of different antigen recognition ** Mature B cells go to the lymph nodes and spleen to await clonal selection by antigen |
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Antibody is also the B Cell Antigen Receptor
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** Each B cell has a uniquely specific receptor ** B cells with differing receptors are produced randomly in the bone marrow --- Variable regions that are the binding site to pathogen -- Constant regions; exactly the same on every antibody |
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Ig gene loci--> |
immunoglobin ** is on a chromosome in each immature B cell |
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Somatic recombination---> |
splicing, DNA excised (taken out), at random V= variable region D=Diversity region J=Junction |
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Where do antibodies come from? STEP 1 |
Pathogen engulfed by Antigen Presenting Cells (ACP)--> group of cells; job to present antigens to immune system. --Antigens are places onto receptors on APC surface - MHC |
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Antigen Presenting Cells are: |
Dendritic cells, Macrophages, and B cells. ** The T cell binds antigen presented on MHC |
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MHC |
Major histocompatibility complex --receptors on host cell that present peptides to the outside world |
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MHC I |
all nucleated cells present "self" |
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MHC II |
APCs present antigen to immune system |
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Where do antibodies come from? STEP 2: |
APC loaded with antigen molecules comes into contact with T helper (Th) cells --APC and Th form a bound receptor complex -Th cell becomes activated ---> clones itself over and over; all the same and able to recognize the same pathogen |
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STEP 3 |
Activated Th cells grow and divide - Activate B cells by similar receptor recognition and binding (clonal selection) |
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STEP 4 |
Activated B cells grow and divide -some become memory cells (activated B cells) -Some become plasma cells --> secrete antibodies -Plasma cells are antibody generating machines (2000 Ab per second!) |
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Antibody functions |
Neutralization Complement fixation Agglutination Opsonization |
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Agglutination: |
Clumps pathogens, makes them easier to phagocytose |
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Neutralization: |
Block cell binding of pathogens and toxins |
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Opsonization: |
coat pathogen for easy phagocytosis |
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Antibody-dependent cell-mediated cytotoxicity (ADCC) ( pathogens that are too big) |
Signals killer cells to kill pathogen |
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There are 5 Classes of antibody |
IgG-Monomer IgA-Dimer, Monomer IgM- Pentamer IgD- Monomer IgE- Monomer |
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IgG: |
Most abundant found later in infection; Can cross placneta |
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IgA: |
Secretory IgA component Secretions |
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IgM: |
Circulating blood found early in infection |
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IgD: |
On B cells Circulating blood |
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IgE: |
Allergy response! helminth infections |
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Monoclonal antibodies |
Every antibody molecule is exactly the same --single epitope --Made from immunized mice -- VERY useful for Diagnosis Therapy Research ** Fuses cancer cell to antibody; making it an immortal antibody |
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Measuring humoral immunity "Serology" |
When someone has antibodies to a pathogen, they are SEROPOSITIVE |
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The amount of antibodies they have is their: |
titer **high titer means a large amount of antibodies in the blood |
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Antibodies are detected by.... |
their functions: agglutination, neutralization, complement lysis |
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Quick diagnostics: |
Rapid strep Test Pregnancy tests |
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Rapid Strep test |
Antibody to group B Streptococcus spp. -Antigen will bind to antibody if positive |
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Pregnancy Tests |
-same principle as rapid strep test - antibodies to HGH are used. When your urine washes over antibodies, they bind triggering the plus sign |
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Neutralizing antibodies |
block virus hemagglutination |
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Passive transfer of antibody |
Antibodies can be given to people who cannot make their own: Natural or Artificial |
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Natural: |
Mothers via transplacental antibodies Mothers via nursing |
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Artificial: |
Transfer antibodies to someone that cannot make their own |
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Treatment for botulism: |
Botulism is caused by Clostridium botulinum -causes paralysis (can't move anything) ---voluntary and involuntary muscles -Only treatment for exposure is injection of horse antibody against toxins -Botox- botulism toxin... |
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Treatment for tents: |
Tents is caused by Clostridium tetani --causes muscle rigidity and spasms ( every muscle is rigid. Deadly; painful) - one treatment for exposure is injection of human antibody against toxin ** aka.. neutralizing antibodies made by another person. |
