chapter 15 specific immunity
TRANSCRIPT
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Specific Immunity
Chapter 15
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SPECIFICITY MEMORY
Fig 14.25
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2 branches of the adaptive immune
system1. ______________immune system- takes
place in body fluids; B cells secrete
antibodies that attack antigens
2. ______________immune system takes
place between the T cells and antigens
(infected, cancerous or other types ofcells.
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____________ (foreign invader) a substance thatis recognized as foreign or nonself by theimmune system. May be a whole microorganismor a portion of it.
___________________- (defensive weapon) a Y-shaped protein which is produced & secreted by Bcells in response to a specific antigen. Antibodiesbind to & contribute to the destruction of antigens.
Antigen
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Structural & chemical
characteristics of antibodies1. Also called _____________________
2. highly specific proteins that interact with only ____
antigenic determinant (_____________) on an antigen
3. serve as __________________receptors for B cells
4. each Ab has ___identical binding sites for___________
5. a typical Ab monomer has ___protein chainsa. 2 identical Light (L) chains
b. 2 identical Heavy (H) chains
6. each H & L chains has a variable region & a constant
region
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Fig 15.5
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variable region - located at the end of the Y arms
account for ability to bind specific Agthousands of possibilities
constant region - located at the stem & lower parts of
the Y arms___major types of constant H regions ( G,M,A,D,E)
___major types of constant L regions ( kappa, lambda)
stem of the Y called Fc region
Fc can bind to host cells
Fc of G & M classes of Ab can activate complement
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Characteristics of each of the 5
classes of antibodies1. IgG
cross placenta & confer passive immunity to fetus
trigger complement system
2. IgM
pentamer 5 monomers & a J chain
trigger complement system
first antibody to appear after initial exposure to Ag
Table 15.2
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3. IgA
high amounts are in mucous, saliva, & breast milk
secretory IgA dimmer- 2 monomers & a J chain & asecretory component
main function is to prevent attachment of pathogens to
mucous membranes
4. IgD
acts as antigen receptor on B cells
No known function in serum
5.IgE bound to mast cells & basophils by Fc end, serve as Ag
receptors & binding causes release of histamine &chemicals allergies
useful against parasitic worms
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Fig 15.14
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Antigen
Epitopes orAntigenic determinants
4
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Whathappens afterantibodies
bind toantigen?1. ____________________ - block virus
attachmentto cell, block toxin's active site
2. ________________________(opsonization, inflammation, lysis)
3. ____________________ - clumps Ag
together-helps phagocytosis
4. __________________ -helps phagocytosis
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Fig 15.16
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Primary vs Secondary immune
responses
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Antibodysecretors
Memorycells
Absecretors
Memory
cells
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Primary immune response
Slower
Weak response
Few specific B & T cells
Few antibodies made
Secondary immune response
Faster
Strong response
More specific B & T cells
Lots of IgG made quickly
Basis for vaccines &booster shots
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Cell mediated immunityT cells
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How does the Cellular Immune System
distinguish between self and nonself?
All body cells have Major HistocompatabilityComplex (MHC) class I proteins on their surfaces
that mark the cells as self Immune system tries to destroy anything that does
not have class I proteins because they are nonself,or antigens
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T cell
Foreignantigen
MHC
T cell receptor recognizes
self MHC plus foreign antigen
Body cell
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T cells Derived from bone marrow and mature in thethymus
Make up _______% of circulating lymphocytes
Each has a T cell antigen receptor which recognizes
a peptide bound to a self MHC molecule
Do not recognize soluble, ______________antigen
Antigen must be displayed on surface of an antigen
presenting cell like a B cell or macrophage
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T cell antigen receptor
Fig 15.7
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3 Types of T cells
Helper T4 Co c o of e sys ec e o e cells of e sys e
Cy o o c T8 es oy e cells o co c
Re l o y T off e espo ses
Self ole ce
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Cytokines
Chemical messengers of the immune cells
Signal cells to move into area, become
active, replicate, etc.
used to communicate among WBCs
Interleukin 1 (IL-1)
Interferon (IFN)
Tumor Necrosis Factor (TNF)
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Humoral
immunity
Cell-mediated
immunity
Cell types B cells, plasma
cells
T cells (3 types)
Secretions Antibodies Cytokines to
communicateAntigens Freely circulating
bacteria, viruses,
etc.
Intracellular
parasites,
transplants, cancer
RequiresT cell
stimulation
Yes Yes