Adaptive immunity

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Adaptive immunity

• How can the immune system recognize so many
  different (previously unseen) insults?
• How does the immune system learn?
• How do B cells produce antibodies?

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Antibody production after immunization
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Irradiation prevents immune response
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Which cells can restore the immune response?
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Origins of lymphocytes
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B cells TC (Cytotoxic T cells) TH (Helper T
cells)
Also function in immune system
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Origins of lymphocytes
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Origins of lymphocytes
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Antibody protein structure
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B cell activation
Each naïve B cell makes a single type of antibody
with a unique binding specificity Upon
activation the naïve B cell proliferates and
produces progeny that secrete that antibody
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Antibody production after immunization
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Clonal selection
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Primary response Secondary response
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Antibody action Activation of Complement
Adaptive immunity (Innate immunity)
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Antibody action Action of Complement
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Antibody action IgG-mediated phagocytosis
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Antibody action IgA is secreted
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Antibody action IgE stimulates histamine
production
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Antibody structure
Determines antibody class
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Human heavy chain gene-segment pool
IgM IgG IgD IgE IgA
51 x 27 x 6 8262 possible H chain variable
regions 40 x 5 200 possible k light chain
variable regions 116 possible l
chain variable regions
2.6 million possible antigen binding sites from
gene segment combinations
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Human heavy chain gene-segment pool
51 x 27 x 6 8262 possible H chain variable
regions 40 x 5 200 possible k light chain
variable regions 116 possible l
chain variable regions
2.6 million possible antigen binding sites from
gene segment combinations
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Human k light-chain gene rearrangement
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Ab gene usage in a pre-B cell (allelic exclusion)
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Clonal selection
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Memory cells Somatic hypermutation in V
regions Class switching