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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?
Antibody production after immunization
Irradiation prevents immune response
Which cells can restore the immune response?
Origins of lymphocytes
B cells
TC (Cytotoxic T cells)
TH (Helper T cells)
Also function
in immune
system
Origins of lymphocytes
Origins of lymphocytes
Antibody protein structure
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
Antibody production after immunization
Clonal selection
Primary response
Secondary response
Antibody action: Activation of Complement
Adaptive immunity
(Innate immunity)
Antibody action: Action of Complement
Antibody action: IgG-mediated phagocytosis
Antibody action: IgA is secreted
Antibody action: IgE stimulates histamine production
Antibody structure
Determines antibody class
Human heavy chain gene-segment pool
IgM IgG
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
IgD
IgE
IgA
2.6 million possible
antigen binding sites
from gene segment
combinations
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
Human k lightchain gene
rearrangement
Ab gene usage in a pre-B cell (allelic exclusion)
Clonal selection
Memory cells:
Somatic hypermutation in V regions
Class switching