Glossary

Definitions of selected terms

Allele
One of two or more alternative forms of a gene, only one of which can be present in a chromosome.
Allelic exclusion
The process by which one allele of a gene is expressed while the other allele is silenced.
Amino acids
These are organic compounds that combine to form proteins.
Antibody
A type of protein made by the body's white blood cells (B lymphocytes) in response to a foreign substance (antigen). The production of antibodies is a major function of the immune system. Some antibodies destroy antigens directly while others make it easier for white blood cells to destroy the antigen. Each antibody is highly specific and will only bind to or destroy the antigen for which it was made.
Antibody specificity
The specificity of an antibody is defined as its capacity to target a specific antigen or foreign substance.
Antigen
Any substance that triggers an immune response, this includes pollen, micro-organisms such as bacteria, viruses, fungi or parasites and non-living substances such as toxins, chemicals, drugs, or foreign particles considered alien to the body.
Antiserum (plural: antisera)
This is serum that contains antibodies. It is obtained from an animal or human that has been exposed to a specific antigen.
B lymphocytes
A type of white blood cell made in the bone marrow that responds to an antigen by producing antibodies.
Bence-Jones proteins
A small protein made by plasma cells found in the urine of most people with multiple myeloma, a cancer that starts in plasma, a type of white blood cell.
Chimeric antibodies
Antibodies with a mixture of human and non-human components. Chimeric antibodies are approximately two-thirds human in form.
Chromatography
A chemical technique used for separating the components of a mixture. During the test a mixture dissolved in a liquid or gas is passed through a column, paper or glass support, where the elements of the mixture are either absorbed or hindered to varying degrees and thereby become separated. The technique is used both for the purification and collection of components as a means to quantify and measure component parts in a mixture.
Culture medium
A liquid or gel designed to aid the growth of micro-organisms or cells.
Disuplhide bridge
The bond that links atoms in a chemical compound.
DNA
This stands for DeoxyriboNucleic acid, and is a complex chemical located in the cell nucleus, specifically contained in chromosomes. It provides the genetic instructions needed for an organism to develop, survive and reproduce.
Enkephalin
Part of the family of opioid peptides produced by the body, enkephalin occurs in the brain, spinal cord and gastrointestinal tract. The peptide is inolved with pain perception, movement, mood, behaviour and neuroendocrine regulation.
Enzyme-linked immunosorbent assay (ELISA)
This is a test that uses antibodies conjugated with a colour enzyme (such as horseradish peroxide, alkaline phosphate or glucose oxidase) to identify a substance. ELISA tests are used as a diagnostic tool in medicine.
Epitope
Part of the target molecule, antigen, recognised by an antibody.
Flow cytometry
A laser based technique for counting and examining microscopic particles, such as cells and chromosomes. The particles are suspended in a stream of fluid which is passed through an electronic detection apparatus.
Fluorescence-activated cell sorting (FACS)
This is a specialised form of flow cytometry that allows for the sorting of a heterogeneous mixture of biological cells into two or more containers. The cells are sorted according to their specific light scattering and fluorescent characteristics.
Histocompatibility antigens
These are the many proteins (antigens) found on the surface of cell membranes that serve to identify a cell as self or non-self. They help determine tissue/organ compatability and rejection in transplantations or blood transfusions.
Humanised antibodies
Antibodies from non-human species whose protein sequences have been re-engineered to increase their similarity to antibody variants produced naturally in humans.
Hybrid cell
A cell formed by fusion of two cells of different origin.
Hybridoma
A hybrid cell made in the laboratory through the fusion of an antibody producing lymphocyte with a non-antibody producing cancer cell, usually myeloma or lymphoma. The hybridoma proliferates and produces a continuous supply of a specific monoclonal antibody.
Immune system
A biological defence system in humans and other mammals that protects the body against the invasion of foreign material (such as pollen, or invading micro-organisms) and helps prevent cancer.
Immunoassay
This is a biochemical test that measures the concentration of a specific substance in blood or a fluid sample which takes advantage of the binding mechanism of an antibody with an antigen.
Immunoglobulin (Ig)
Also known as an antibody, this is a protein produced by the immune system to fight infection.
Immunohistochemistry
A laboratory technique that uses antibodies to detect and visualise antigens in cells and tissues.
Immunology
The investigation of all phenomena connected with the defence mechanism of the body.
Interferon
A small protein messenger produced by the immune system in response to the presence of pathogens such as viruses, bacteria, parasites or tumour cells. Interferon has two functions. It sends signals to neighbouring cells to trigger their resistance mechanisms, and it activates other immune cells that kill invading pathogens.
Lymphocytes
A type of white blood cell which plays an important role in the body's defence mechanism. The two primary types of lymphocytes are B lymphocytes (B-cells) and T lymphocytes (T cells). Both originate from stem cells in the bone marrow. Those that migrate to the thymus mature into T cells, while those that remain in the bone marrow develop into B cells. Each lymphocyte has a receptor molecule on its surface which it uses to bind antigens (foreign substances) and help to remove them from the body. In the presence of an antigen, B cells can differentiate into plasma cells which secrete large quantities of antibodies.
Monoclonal
Derived from a single cell.
Monoclonal antibody
This is an antibody produced from a single clone of cells in a laboratory. The advantage of monoclonal antibodies is that they can be made on a large-scale and each one is identical to the other. Highly specific in their target, monoclonal antibodies are today used as reagents for basic research tools, and as diagnostic tools and therapeutics. In the context of therapy monoclonal antibodies can be used alone, or they can be used to deliver drugs, toxins, or, in the case of cancer, radioactive material directly to a tumour.
Myeloma
A cancer of plasma cells, a type of white blood cell found in the bone marrow.
Myeloma cells
Plasma cells that have become cancerous. Myeloma cells can spread throughout the bone marrow and into the bone, causing thinning of the bone, pain and sometimes fractures. Such cells produce a large amount of a single type of abnormal antibody. Myeloma cells are an essential tool for monoclonal antibody production.
Neuropeptide
Small, protein-like substance produced and released by neurons which helps neurons communicate with each other.
Neurotransmitter
A brain chemical that relays signals between nerve cells called neurons. Neurotransmitters tell the heart to beat, lungs to breathe and the stomach to digest. They can also affect mood, sleep, concentration, weight and can cause adverse reactions when imbalanced.
Patent
A patent is a form of intellectual property rights granted by a government to an inventor or their assignee for a limited amount of time in exchange for the public disclosure of the invention. A patent provides the right to exclude all others from making, using, or selling an invention or products made by an invented process. Like any other property right, it may be sold, licensed, assigned or transferred, given away or simply abandoned.
Polyclonal
Mixed pool of antibodies produced in an animal by a number of different white blood cells in response to an antigen. Each antibody has different binding specificities.
Polyethylene glycol (PEG)
A petroleum derived compound with many applications from industrial manufacturing to medicine.
Radioimmunoassay
This is an immunoassay test which makes use of radioactively labelled antibodies and antigens to detect and quantify important substances, such as hormone levels in the blood.
Recombinant DNA
Also known as gene cloning or splicing, recombinant DNA is a technique that produces identical copies (clones) of a gene.
Restriction enzymes
These are DNA-cutting enzymes found in and harvested from bacteria. The advantage of a DNA-digesting enzyme is that it can cleave the DNA molecule at precisely-located sites. Each enzyme recognises and cuts DNA at a particular sequence of nucleotides.
Sendai virus
A virus that affects mice, hamsters, guinea pigs, rats and sometimes pigs which is used research laboratories for its ability to induce genetically different cells to fuse.
Serotonin
A compound widely distributed in the tissues, particularly in blood platelets, intestinal wall and central nervous system. It is thought to play a part in transmitting nerve impulses and regulating moods, temper, anxiety, depression, sleep, aggression, appetite and sexuality. Serotonin is also considered instrumental in regulating body temperature and metabolism.
Serum
The straw coloured liquid component of blood from which blood cells and the chemicals which cause clotting have been taken out.
Somatic cell
Any cell type in the mammalian body apart from the sperm and ova.
Somatic mutation
The alteration of DNA that occurs after conception. Such changes can happen in any of the cells of the body except germline cells (sperm and ova) and so cannot be passed on to offspring. The alteration can cause various diseases including cancer.
Spleen
An organ that plays an important role in the immune system and helps in the creation of red blood cells. The spleen removes old red blood cells and recycles iron. It also synthesises antibodies and removes from circulation antibody-coated bacteria and antibody-coated blood cells.
Substance P (SP)
A small peptide found in the spinal cord and brain that transmits pain signals from the sensory nerves to the central nervous system. It is also associated with the regulation of stress and anxiety.
Supernatant
This is the upper layer of fluid found after a mixture has been centrifuged.
Tissue culture
A technique used to keep tissues or cells alive separate from an organism.

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