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Cytokines are
chemical signals from one cell that influences another.
small protein hormones
control cell growth and differentiation
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What are the types of cytokines?
- Interferon
- interleukins
- Erythropoietin
- Tumor necrosis factor
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Interleukins
cytokines between white blood cells
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Interferon
Anti-viral properties and stimulator of the immune system
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Tumor-necrosis factor (TNF)
Produced by macrophages to encourage inflammation.
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Erythropoietin
cytokine from the kidneys, increases the number and activity of rec ell precursors in bone marrow.
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Antibodies (also called immunoglobulins (Ig) are produced in response
to antigen through antibody-mediated immunity
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Antibodies have four peptide chains
2 heavy chains and two light chains.
Disulfide bonds link the chains together in a Y-shaped arrangement.
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Antibodies:
Variable & Constant Regions. Describe both.
Variable region (antigen-binding region)- Gives an antibody its specificity
Constant region- similar for each class of antibody
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Antibodies:
Antibody Functions
Neutralizing antigen
- Restricting virus binding to receptors
- Toxin neutralization
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Antibodies:
Antibody Functions
Immobilizing bacteria
Binding to cilia and flagella
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Antibodies:
Antibody Functions
Agglutinating and precipitating antigen
Making what is soluble, insoluble
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Antibodies:
Antibody Functions
Activating complement
Classical pathway
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Antibodies:
Antibody Functions
Enhancing phagocytosis
Opsonization
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Antibody class:
General structure, location, and function
IgG
Monomer, two antigen-binding sites, found in blood, lymph and intestines, 80% of the antibody in the blood, only class to cross the placenta, provide long-term immunity
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Antibody class:
General structure, location, and function
IgM
Pentamer, 10 antigen-binding sites, first to be secreted by plasma cells, great complement activator, short-lived
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Antibody class:
General structure, location, and function
IgA
Dimer, four antigen-binding sites, found in sweat, tears, saliva, mucus, breast milk, and gastrointestinal secretions, levels decrease during stress
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Antibody class:
General structure, location, and function
IgE
Monomer, two antigen-binding sites, less than 0.1% of antibody in the blood, located on mast cells in tissue
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Antibody class:
General structure, location, and function
IgD
Monomer, two antigen-binding sites, 0.2% of antibody in the blood, found as receptors for antigen on B-cells
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Acquired Adaptive Immunity
Natural Immunity- immunity not gained through modern medicine.
Artificial Immunity- gained through artificial means
Active Immunity- The body responds to a pathogen (antigen) to make antibodies (long-term immunity)
Passive Immunity- The body receives antibodies with no effort of its own (short-term immunity)
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Active immunity is long-term; passive is
short-term
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Acquiring Adaptive Immunity
Method:
Naturally-acquired active immunity
Immune products acquired following exposure to antigen
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Acquiring Adaptive Immunity
Method:
Naturally-acquired passive immunity
Transfer of antibody from non-medical source; IgG through the placenta, IgA through breast milk
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Acquiring Adaptive Immunity
Method:
Artificially-acquired active immunity
Immune products acquired through vaccination; antigens given that are immunogenic but not pathogenic.
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Acquiring Adaptive Immunity
Method:
Artificially-acquired passive immunity
Prepared injection of antibody
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The Complement System
- A very powerful group of proteins that "complement" the action of the immune system
- The main proteins are c1-c9
- Activated by multiple pathways in a step-wise or cascading fashion
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The Complement System functions are
- Encourages vasodilation and inflammation
- Antigen opsonization
- Destroys antigen
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Formation of Antibodies
Primary antibody-mediated response
-1st exposure
- 5-7 day delay
- Production of IgM followed by IgG
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Formation of Antibodies
Secondary antibody-mediated response
- Second and subsequent exposures
- Very little delay due to memory T-helper and B cells
-Production of IgM followed by a long-lasting population of IgG
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Self-recognition
ability to recognize one's own cellular markers
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Self-tolerance
The immune system must leave self-antigens alone
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Failure of self-recognition or self-tolerance results in
autoimmune disease
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The Immune System and Aging
Atrophy of the thymus gland
- Decreased T-helper cell population- diminished mediation of the specific-immune response (decreased B-cell response)
- Decreased number of T-cytotoxic cells- increased incidence of cancer
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The Immune System and Aging
Increased numbers of
autoantibodies
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