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serotherapy 647 serum hepatitis (hepatitis B)
serotherapy
A form of treatment for infectious disease developed almost
a century ago in which antiserum raised by immunizing
horses or other animals against exotoxin, such as that
produced by Corynebacterium diphtheriae, was administered
to children with diphtheria. This antitoxin neutralized
the injurious effects of the toxin; thus, serotherapy was
intended for prevention and treatment.
H N
HO CH 2 CH 2 NH 2
Structural formula of serotonin (5-hydroxytryptamine) released during and
participates in the mediation of anaphylactic reactions in some species and
not others.
serotonin (5-hydroxytryptamine; 5-HT)
A 176-kDa catecholamine found in mouse and rat mast
cells and in human platelets that participates in anaphylaxis
in several species such as rabbits, but not in humans. It
induces contraction of smooth muscle, enhances vascular
permeability of small blood vessels, and induces large blood
vessel vasoconstriction. 5-HT is derived from tryptophan by
hydroxylation to 5-hydroxytryptophan and decarboxylation
to 5-hydroxytryptamine. In humans, gut enterochromaffin
cells contain 90% of 5-HT, with the remainder accruing in
platelets and the brain. 5-HT is a potent biogenic amine with
wide species distribution. It may stimulate phagocytosis by
leukocytes and interfere with the clearance of particles by the
mononuclear phagocyte system. Immunoperoxidase staining
for 5-HT, which is synthesized by various neoplasms, especially
carcinoid tumors, is a valuable aid in surgical pathologic
diagnosis of tumors producing it.
serotype
The mosaic of epitope of a microorganism defined by specific
antibodies.
serotyping
The use of specific antibodies to classify bacterial subtypes
based on variations in the surface epitopes of the
microorganism. Serotyping has long been used to classify
Salmonella, streptococci, Shigella, and other bacteria. May
also describe human alloantigens such as human leukocyte
antigen (HLA) and blood group antigens.
serpins
A large family of protease inhibitors.
serum
The yellow-tinged fluid that forms following blood coagulation.
Plasma contains fibrinogen, but serum does not; thus,
serum is the part of plasma that remains after removal of
fibrinogen and clotting factors. Serum contains 35 to
55 mg/mL of serum albumin, approximately 20 mg/mL of
immunoglobulins, 3 mg/mL each of transferrin and α-1
antitrypsin, 2.5 mg/mL of α 2 macroglobulin, and 2 mg/
mL of haptoglobin. It is more convenient to use serum than
plasma in immune reactions since clotting may interfere
with certain assays.
serum albumin
The principal protein in serum or plasma. It is soluble in
water and in partially concentrated salt solutions such as 50%
saturated ammonium sulfate. It is coagulated by heat and
accounts for much of the plasma colloidal osmotic pressure.
Serum albumin functions as a transport protein for fatty
acids, bilirubin, and other large organic anions. It also carries
selected hormones including cortisol and thyroxine and many
drugs. It is formed in the liver. Levels in the serum decrease
under conditions of protein malnutrition or significant liver
and kidney disease. In neutral pH, albumin has a negative
charge, causing its rapid movement toward the anode during
electrophoresis. It is composed of a single 585-amino acid
residue chain and has a concentration of 35 to 55 mg/mL.
Bovine serum albumin (BSA) and selected other serum albumins
have been used as experimental immunogens.
serum amyloid A (SAA) component
A 12-kDa protein in serum that is a precursor of the AA
class of amyloid fibril proteins. SAA is formed in the liver
and associates with HDL3 lipoproteins in the circulation. It
is a 114-amino acid residue polypeptide chain. Its conversion
to AA involves splitting of peptides from both amino
and carboxyl terminals to yield an 8.5-kDa protein that
forms fibrillar amyloid deposits. SAA levels during inflammation
may increase 1000-fold.
serum amyloid P (SAP) component
A serum protein that constitutes a minor second component
in all amyloid deposits. Under electron microscopy, it
appears as a doughnut-shaped pentagon with an external
diameter of 9 nm and an internal diameter of 4 nm. Each
pentagon has five globular subunits. The amyloid P component
in serum consists of two doughnut-shaped structures.
Unlike the serum amyloid A component, the P component
does not increase during inflammation. It constitutes 10%
of amyloid deposits and is indistinguishable from normal α 1
serum glycoprotein. This 180- to 212-kDa substance shows
close structural homology with C-reactive protein.
serum antitoxins
Antibodies specific for exotoxins produced by selected
microorganisms such as the causative agents of diphtheria
and tetanus. Prior to the use of antibiotics, antitoxins were
the treatments of choice for diseases produced by the exotoxin
products of microorganisms such as Corynebacterium
diphtheriae and Clostridium tetani.
serum hepatitis (hepatitis B)
An infection with a relatively long incubation lasting 2
to 5 months, caused by a double-stranded DNA virus.
Transmission may be via administration of serum or blood
products. Other high risk groups include drug addicts,
dialysis patients, healthcare workers, male homosexuals,
and newborns with human immunodeficiency virus (HIV)infected
mothers. Chronic infection may occur in immunosuppressed
individuals or those with lymphoid cancer.
The infection may be acute or chronic, and hepatocellular
carcinoma may be a complication. In acute HBV infection,
the hepatocytes may undergo ballooning and eosinophilic
degeneration. Focal necrosis of hepatocytes and lymphocytic
infiltration of the portal areas and liver parenchyma
may occur, in addition to central and mid-zonal necrosis of
hepatocytes. Chronic type B hepatitis may progress to cirrhosis
and hepatocellular carcinoma. Hepatocellular injury
is induced by immunity to the virus. HBsAg, HBeAg, and
IgM anti-HBc are present in the serum in acute hepatitis.
In the convalescent phase of acute hepatitis, IgG anti-HBs
appears in the serum. HBsAg, HBeAg, IgG anti-HBc in
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