Virtual Immunology Lab Glossary
Aliquot - a portion of a solution
Antibody - a type of protein
called an immunoglobulin found in the blood that is produced by
immune cells in response to the presence of a foreign particle
(antigen). Antibodies are specific to each different type of
- Primary : first antibody used in an
immunoassay to detect the foreign particle; in this case, we
are testing to see if the serum from the patients contains
primary antibodies to SLE.
- Secondary antibody: the
second antibody used in an immunoassay that detects the
primary antibody. Note, this antibody must be made in a
different species (rabbit, donkey, horse) than the primary
antibody, in order to recognize the primary antibody as
"foreign". In this case, we are using HRP-tagged rabbit
anti-human antibodies as our secondary antibody.
Antibody-Enzyme Conjugate - antibodies (usually secondary
antibodies) are "tagged" or joined to enzymes through a
chemical process. Now the antibody is carrying an enzyme, so
wherever the secondary antibody binds, the enzyme is present
Antigen - any substance (usually a protein or carbohydrate)
that induces the production of antibodies by immune cells.
Usually is a substance that is "foreign" to the host.
Antigenic Site - the part of the antigen that is
recognized by the antibody
Assay - an examination or test
Centrifuge - an instrument used to spin tubes to
separate solutions into different phases (liquid or solid). In
this example, the red blood cells and other blood components
are "spun out" of the blood, creating two layers in the tube:
components below and serum above.
ELISA - Enzyme-Linked Immunosorbent Assay; this is an
assay that uses an enzyme linked to an antibody. In
this experiment, a colorless substrate is turned into
a colored product by the bound enzyme.
The amount of activity of this enzyme (as determined by
detection of the amount of colored product) is used as a
measurement of the amount of bound antibody.
Enzyme - a protein that acts as a
agent or catalyst to induce chemical changes in other substances.
An enzyme can be used repeatedly, because it is unchanged by
Eppendorf® pipette - an instrument
in the lab used to dispense small volumes of liquids
(milliliters or microliters usually)
HRP - horseradish peroxidase; an enzyme
used to stimulate the conversion of the colorless substrate into
a colored product in this exercise
Humoral Immunity - this refers to the resistance that
results from the presence of the specific antibody within the serum
Nanometers (nm) - a unit of measurement, in this case,
one-billionth of a meter (10-9 m)
Pipettor - a piece of equipment used to transfer a specified volume of a liquid
Sera/Serum - a clear watery fluid obtained
after removing blood cells and other components from blood by
centrifugation that will contain antibodies
Serial Dilutions - when the samples
are diluted in a specific, systematic manner (1:2; 1:10; 1:100)
to determine the concentration of a sample or the sensitivity
of an assay
Spectrophotometer - an instrument for measuring the
intensity of light of a specific wavelength transmitted by a
substance. In this example, it will determine the amount of a
reaction product which is absorbing the light in a solution.
Substrate - any substance
on which an enzyme can act. In this example, HRP
(the enzyme) will interact with a substrate called
ABTS (2,2'-azinobis-3-ethylbenzothiazoleine-6-sulfonic acid)
to produce a yellow solution.
Systemic Lupus Erythematosus (SLE)
Lupus is believed to be an autoimmune disease. The cause
of lupus has yet to be determined. The immune system is
your body's defense mechanism against foreign particles called antigens. Sometimes the immune system loses the
ability to distinguish between its own body components and
antigens. Instead of fighting antigens, the antibodies
mistakenly fight the body's own cells. This
is referred to as an autoimmune response (auto means
self) and the body mistakenly makes autoantibodies.
A systemic disease is one in which several different
parts of the body may be affected. In systemic lupus,
these include the skin, kidneys, nervous system,
lungs, heart and/ or blood-forming organs.
Titer - the concentration of
a substance in a solution. For instance, the amount of
a specific antibody in the serum.