Adapted by Mary
- Acquired immunodeficiency syndrome
- A life-threatening disease caused by a virus and characterized by
breakdown of the body's immune defenses.
- Active immunity:
- Immunity produced by the body in response
to stimulation by a disease-causing organism or a vaccine.
- An almost total
lack of immunoglobulins, or antibodies.
- Any substance that causes an allergy.
- An inappropriate
and harmful response of the immune system to normally harmless substances.
- Anaphylactic shock:
- A life-threatening
allergic reaction characterized by a swelling of body tissues including the throat, difficulty in breathing,
and a sudden fall in blood pressure.
- A state of unresponsiveness, induced when
the T cell's antigen receptor is stimulated, that effectively freezes T cell responses pending a "second
signal" from the antigen-presenting cell (co-stimulation).
- A soluble protein molecule produced and
secreted by B cells in response to an antigen, which is capable of binding to that specific antigen.
- Antibody-dependent cell-mediated cytotoxicity
- An immune response in which antibody, by coating target cells,
makes them vulnerable to attack by immune cells.
- Any substance that, when introduced into
the body, is recognized by the immune system.
- Antigen-presenting cells:
- B cells, cells of
the monocyte lineage (including macrophages as well as dendritic cells), and various other body cells that
"present" antigen in a form that T cells can recognize.
- Antinuclear antibody (ANA):
- An autoantibody directed
against a substance in the cell's nucleus.
- Serum that contains antibodies.
that interlock with and inactivate toxins produced by certain bacteria.
- Lymphoid organ in the intestine.
no longer infectious.
- An antibody that reacts against
a person's own tissue.
- A disease that results when the immune system mistakenly attacks
the body's own tissues. Rheumatoid arthritis and systemic lupus erythematosus are autoimmune diseases.
microscopic organism composed of a single cell. Many but no all bacteria cause disease.
- A white blood
cell that contributes to inflammatory reactions. Along with mast cells, basophils are responsible for the
symptoms of allergy.
- Small white blood cells crucial to the immune defenses. Also known
as B lymphocytes, they are derived from bone marrow and develop into plasma cells that are the source
- Biological response
- Substances, either natural or synthesized, that boost, direct, or
restore normal immune defenses. BRMs include interferons, interleukins, thymus hormones, and
- The use of living organisms
or their products to make or modify a substance. Biotechnology includes recombinant DNA techniques
(genetic engineering) and hybridoma technology.
- Bone marrow:
- Soft tissue located in the cavities of the bones.
The bone marrow is the source of all blood cells.
- Cellular immunity:
- Immune protection provided by the direct
action of immune cells (as distinct from soluble molecules such as antibodies).
- Physical structures in the cell's
nucleus that house the genes. Each human cell has 23 pairs of chromosomes.
- (n.)A group of genetically identical cells or
organisms descended from a single common ancestor; (v.) to reproduce multiple identical copies.
complex series of blood proteins whose action "complements" the work of antibodies. Complement
destroys bacteria, produces inflammation, and regulates immune reactions.
- Complement cascade:
- A precise sequence
of events usually triggered by an antigen-antibody complex, in which each component of the complement
system is activated in turn.
- That part of an antibody's structure that is characteristic for each
- The delivery of a second
signal from an antigen-presenting cell to a T cell. The second signal rescues the activated T cell from
anergy, allowing it to produce the lymphokines necessary for the growth of additional T cells.
chemical substances secreted by cells. Cytokines include lymphokines produced by lymphocytes and
monokines produced by monocytes and macrophages.
- Cytotoxic T cells:
- A subset of T lymphocytes that can kill body
cells infected by viruses or transformed by cancer.
- Dendritic cells:
- White blood cells found in the spleen and other
lymphoid organs. Dendritic cells typically use threadlike tentacles to enmesh antigen, which they present
to T cells.
- DNA (deoxyribonucleic
- Nucleic acid that is found in the cell nucleus and that is the carrier
of genetic information.
- A protein, produced by living cells, that
promotes the chemical processes of life without itself being altered.
- A white blood cell that contains
granules filled with chemicals damaging to parasites, and enzymes that damp down inflammatory
unique shape or marker carried on an antigen's surface, which triggers a corresponding antibody
of a class of relatively primitive vegetable organism. Fungi include mushrooms, yeasts, rusts, molds, and
- A unit of
genetic material (DNA) that carries the directions a cell uses to perform a specific function, such as
making a given protein.
- Graft-versus-host disease
- A life-threatening reaction in which transplanted
immunocompetent cells attack the tissues of the recipient.
- White blood cells filled with
granules containing potent chemicals that allow the cells to digest microorganisms, or to produce
inflammatory reactions. Neutrophils, eosinophils, and basophils are examples of granulocytes.
- Helper T cells:
subset of T cells that typically carry the T4 marker and are essential for turning on antibody production,
activating cytotoxic T cells, and initiating many other immune responses.
- The formation and development
of blood cells, usually takes place in the bone marrow.
- Histocompatibility testing:
- A method
of matching the self antigens (HLA) on the tissues of a transplant donor with those of the recipient. The
closer the match, the better the chance that the transplant will take.
- HIV (human immunodeficiency virus):
- The virus that
- Human leukocyte antigens
- Protein in markers of self used in histocompatibility testing. Some
HLA types also correlate with certain autoimmune diseases.
- Humoral immunity:
- Immune protection
provided by soluble factors such as antibodies, which circulate in the body's fluids or "humors,"
primarily serum and lymph.
- A hybrid cell created by fusing a B
lymphocyte with a long-lived neoplastic plasma cell, or a T lymphocyte with a lymphoma cell. A B-cell
hybridoma secretes a single specific antibody.
rmally low levels of immunoglobulins.
- The unique and characteristic parts of an
antibody's variable region, which can themselves serve as antigens.
- Immune complex:
- A cluster of interlocking
antigens and antibodies.
- The reactions of the immune system to foreign substances.
test using antibodies to identify and quantify substances. Often the antibody is linked to a marker such
as a fluorescent molecule, a radioactive molecule, or an enzyme.
- Capable of developing
an immune response.
- A family of large protein
molecules, also known as antibodies.
- Reduction of the
immune responses, for instance by giving drugs to prevent transplant rejection.
monoclonal antibody linked to a natural toxin, a toxic drug, or a radioactive substance.
- Redness, warmth, swelling, pain, and loss of function produced
in response to infection, as the result of increased flood flow and an influx of immune cells and
- A major group of lymphokines and
- Specialized macrophages in the liver.
- LAK cells:
- Lymphocytes transformed in the
laboratory into lymphokine-activated killer cells, which attack tumor cells.
- Langerhans cells:
- Dendritic cells in the skin
that pick up antigen and transport it to lymph nodes.
- All white blood cells.
- A transparent,
slightly yellow fluid that carries lymphocytes, bathes the body tissues, and drains into the lymphatic
- A bodywide network of channels, similar to the blood vessels,
which transport lymph to the immune organs and into the bloodstream.
- Lymph nodes:
- Small bean-shaped organs of the
immune system, distributed widely throughout the body and linked by lymphatic vessels. Lymph nodes
are garrisons of B, T, and other immune cells.
- Small white blood cells produced
in the lymphoid organs and paramount in the immune defenses.
- Lymphoid organs:
- The organs of the
immune system, where lymphocytes develop and congregate. They include the bone marrow, thymus,
lymph nodes, spleen, and various other clusters of lymphoid tissue. The blood vessels and lymphatic
vessels can also be considered lymphoid organs.
- Powerful chemical substances
secreted by lymphocytes. These soluble molecules help direct and regulate the immune responses.
- A large
and versatile immune cell that acts as a microbe-devouring phagocyte, an antigen-presenting cell, and an
important source of immune secretions.
histocompatibility complex (MHC):
- A group of genes that controls several
aspects of the immune response. MHC genes code for self markers on all body cells.
- Mast cell:
granule-containing cell found in tissue. The contents of mast cells, along with those of basophils, are
responsible for the symptoms of allergy.
- Minute living organisms, including
bacteria, viruses, fungi and protozoa.
- Microscopic plants or
smallest amount of a specific chemical substance that can exist alone. (The break a molecule down into
its constituent atoms is to change its character. A molecule of water, for instance, reverts to oxygen and
- Antibodies produced by a single cell or its identical progeny,
specific for a given antigen. As a tool for binding to specific protein molecules, monoclonal antibodies
are invaluable in research, medicine, and industry.
- A large phagocytic white blood cell
which, when it enters tissue, develops into a macrophage.
- Powerful chemical substances secreted
by monocytes and macrophages. These soluble molecules help direct and regulate the immune responses.
- Natural killer (NK)
- Large granule-filled lymphocytes that take on tumor cells and infected
body cells. They are known as "natural" killers because they attack without first having to recognize
- A white blood cell that is an abundant
and important phagocyte.
- Large, naturally occurring molecules composed of chemical building
blocks known as nucleotides. There are two kinds of nucleic acids, DNA and RNA.
- A monoclonal
antibody that targets mature T cells.
- Opportunistic infection:
- An infection in an immunosuppressed
person caused by an organism that does not usually trouble people with healthy immune systems.
- To coat an
organism with antibodies or a complement protein so as to make it palatable to phagocytes.
- An individual
plant or animal that lives, grows and feeds on or within another living organism.
- Immunity resulting from the transfer of antibodies or antiserum
produced by another individual.
- A collection of lymphoid tissues in the intestinal tract.
white blood cells that contribute to the immune defenses by ingesting microbes or other cells and foreign
- Large antibody-producing cells that develop from B cells.
- Granule-containing cellular fragments
critical for blood clotting and sealing off wounds. Platelets also contribute to the immune response.
for polymorphonuclear leukocytes or granulocytes.
- Organic compounds made up of amino
acids. Proteins are one of the major constituents of plant and animal cells.
- A group of one-celled animals, a few of
which cause human disease (including malaria and sleeping sickness).
- Rheumatoid factor:
- An autoantibody found
in the serum of most persons with rheumatoid arthritis.
- RNA (ribonucleic acid):
- A nucleic acid that is found
in the cytoplasm and also in the nucleus of some cells. One function of RNA is to direct the synthesis
- Any of a diverse group of cells that have the capacity to engulf and
destroy foreign material, dead tissues, or other cells.
- SCID mouse:
- A laboratory animal that, lacking an enzyme
necessary to fashion an immune system of its own, can be turned into a model of the human immune
system when injected with human cells or tissues.
- The clear liquid that separates from the blood
when it is allowed to clot. This fluid retains any antibodies that were present in the whole blood.
- Severe combined immunodeficiency disease
- A life-threatening condition in which infants are born lacking all
major immune defenses.
- A lymphoid organ in the abdominal cavity that
is an important center for immune system activities.
- Stem cells:
- Cells from which all blood cells derive. The bone
marrow is rich in stem cells.
- A vaccine that uses merely one component of an infectious agent,
rather than the whole, to stimulate an immune response.
- A class of antigens, including
certain bacterial toxins, that unleash a massive and damaging immune response.
- Suppressor T
- A subset of T cells that turn off antibody production and other
- Small white blood cells that orchestrate and/or directly participate
in the immune defenses. Also known as T lymphocytes, they are processed in the thymus and secrete
primary lymphoid organ, high in the chest, where T lymphocytes proliferate and mature.
lymphocytes. These immune cells are extracted from the tumor tissue, treated in laboratory, and
reinjected into the cancer patient.
- See histocompatibility testing.
- A state of nonresponsiveness to a
particular antigen or group of antigens.
- Tonsils and adenoids:
- Prominent oval masses of lymphoid
tissues on either side of the throat.
- Agents produced by plants and bacteria,
normally very damaging to mammalian cells, that can be delivered directly to target cells by linking them
to monoclonal antibodies or lymphokines.
- A substance that contains antigenic
components from an infectious organism. By stimulating an immune response (but not disease), it protects
against subsequent infection by that organism.
- Variable region:
- That part of an antibody's structure that differs
from one antibody to another.
- Submicroscopic microbe that causes infectious
disease. Viruses can reproduce only in living cells.
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