Humoral immune response
Type of adaptive immune response
mediated by antibodies that
neutralize and eliminate
extracellular pathogens and their
toxins
Cell mediators of humoral immunity
are B lymphocites
Functions of antibodies
Humoral immune response
Thymus-dependant
(T-dependant)
Thymus-independant
(T-independant)
Cells that respond to thymus-dependent antigens
Spleen,
other
lymphoid
organs
Functional consequences of B-cell activation
Phases of humoral immune response
Interaction of helper T- cells and B-cells
in peripheral lymphoid tissues
Antigen recognition and presentation by B-cells
Interaction of helper T- cells and B-cells
in peripheral lymphoid tissues
T- and B-cell cooperation
Antibody affinity maturation
• Process of increasing the affinity of the
antibody in prolong or repeated exposure to the
same antigen
• It takes place in germinative centers of lymphoid
follicules
• Underlying mechanism is:
– somatic mutation of gene for variable region of Ig in
proliferating B-cells and selection of B-cells with
high-affinity receptor for that antigen
Hypermutation of Ig V genes
Intensive proliferation
Activated B go to
germinative center
Somatic hypermutations of Ig V genes
Somatic mutation
Selection
High-affinity plasma
and memory cells
leave germinative
center
B not recognizing Ag on
FDC die by apoptosis
B recognizing Ag on
FDC survive
Hypermutation of Ig
V genes
Intensive proliferation
Activated B go to
germinative center
Regulation of humoral immune response
Antibody feed-back regulation
• Process where Ab bound to Ag inhibits
further Ab production
• Purpose: humoral immune response
termination upon sufficient IgG production
Mechanism of feed back regulation by Abs
Antibody feed-back regulation
Clinical application
• In therapy of some autoimmune
inflammatory diseases
IgG of numerous donors (IVIG)
- engage inhibitory FcR on B-cells and
inhibit pathological immune response
Amounth of antibody
Primary and secondary humoral immune
response
Primary response
First exposure
to the antigen
Secondary response
Repeated exposure to the
antigen
Humoral immune response to thymus-independent antigens
Encapsulated bacteria
IgM
B-cell
Cells that respond to thymus-independent antigens
Spleen
1. Adaptive humoral immune response is
mediated by
2. Humoral immune response is important
in defense aginst
3. Humoral immune response to nonprotein antigens is
a. IgM
b. B-cells of marginal zone in spleen
c. quantitatively and qualitatively different
(faster, stronger and more efficient)
4. Cells that respond to polysaccharides in
blood are
5. In response to thymus-independent
antigens mostly is produced
d. CD4+ T-cells
6. Cells that respond to proteins are
f. antibodies
7. Humoral immune response to protein
antigens necessary is the participation of
8. Features of humoral immune response to
thymus-dependent antigens are
g. thymus-independent
9. Secondary humoral immune response,
compared to primary , is
e. isotype switch, affinity matturation and
memory B-cell development
h. antibody feed-back regulation
i. follicular B-cells
10. Phenomenon of inhibition of antibody
j. extarcellular microorganisms and their toxins
production by antibody bound to antigen is
1.____
f
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j
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g
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b
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a
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i
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d
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e
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h