Unit 1 Nature of the Immune System
Part 3 Acute Phase Reactants
Terry Kotrla, MS, MT(ASCP)BB
Immunity – Very Complex System
Soluble Factors
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Many soluble tissue and serum substances help to suppress
the grow of or kill microorganisms.
Interferons - family of proteins which are important nonspecific defense mechanisms against viral infections.
Transferrin - Bacteria do not thrive well in serum that
contains low levels of iron but high levels of transferrin.
Complement - a group of proteins that are essential for
bacterial destruction and plays an important role in both nonspecific and specific immune mechanisms.
Acute Phase Reactants (Proteins)
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Defined-normal serum constituents that increase rapidly
because of infection, injury, or trauma to tissues.
Acute-phase proteins are a class of proteins whose plasma
concentrations increase or decrease in response to
inflammation.
This response is called the acute-phase reaction .
In response to injury local inflammatory cells (neutrophils,
granulocytes and macrophages) secrete a number of cytokines
into the bloodstream, most notable of which are the
interleukins.
The liver responds by producing a large number of acutephase reactants.
C-Reactive Protein
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Increases rapidly within 4-6 hours of infection
or injury.
Returns to normal rapidly once condition
subsides.
Used to monitor healing and has also
increased in usefulness in diagnosing
Myocardial Infarction.
Serum Amyloid A
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Major protein secreted during the acute phase
of inflammation.
Has several roles, including
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Removes cholesterol from cholesterol-filled
macrophages at site of injury – clean up.
recruitment of immune cells to inflammatory
sites, and
Thought to play a role in cholesterol metabolism
Complement
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A series of serum proteins involved in
mediation of inflammation but also involved
in
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opsonization,
chemotaxis, and
cell lysis.
Alpha-1 Antitrypsin
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Increases during acute inflammation.
Protects tissues from enzymes of inflammatory cells,
especially elastase.
When the lungs do not have enough alpha-1
antitrypsin, elastase is free to destroy lung tissue.
As a result, the lungs lose some of their ability to
expand and contract (elasticity). This leads to
emphysema and sometimes makes breathing
difficult.
Haptoglobin
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Binds irreversibly to free hemoglobin to
protect kidneys from damage and prevent loss
of iron by urinary excretion.
Haptoglobin - hemoglobin complex removed
by RES, mainly spleen.
Used to monitor hemolysis
Fibrinogen
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A coagulation factor integral to clot formation
which serves as a barrier to prevent spread of
microorganisms further in the body.
Levels increase with tissue inflammation or
tissue destruction.
Thought to play a key role in the
inflammatory response and development of
rheumatoid arthritis.
Ceruloplasmin
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Principal copper transporting protein in plasma, plays a role
in iron metabolism and histamine regulation.
Stimulates the immune system to fight infections, repair
injured tissues and promote healing.
Depletion found in Wilson’s disease, causes the body to
absorb and retain excessive amounts of copper.
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Copper deposits in the liver, brain, kidneys, and the eyes.
The deposits of copper cause tissue damage, necrosis (death of the
tissues), and scarring, which causes decreased functioning of the
organs affected.
Liver failure and damage to the central nervous system (brain, spinal
cord) are the most predominant, and the most dangerous, effects of
the disorder.
References
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http://www.horton.ednet.ns.ca/staff/Selig/isu/Immunity/Innate.htm
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http://www.metacafe.com/tags/neutrophil/most_popular/