Dirty, rotten swine flu – and how to beat it
Glossary
adjuvant. A substance that increases the effectiveness of a vaccine. Adjuvants used in combination with vaccine antigens enhance the body’s immune response. Examples include aluminium salts, oil-water emulsions and some detergent materials.
allantoic cavity. The cavity of the allantois within an egg, a membranous sac which is involved in gas exchange, storage of wastes and absorption of nutrients for the developing chick embryo. For a diagram see The anatomy of a ten-day old embryonated egg (Food and Agriculture Organisation of the United Nations).
antibody. A protein produced by the body’s immune system in response to a foreign substance (antigen). An antibody reacts specifically with the antigen that induced its formation to help the immune system inactivate a toxin or microorganism. Our bodies fight off an infection by producing antibodies.
antigen. Any foreign substance, usually a protein, that stimulates the body's immune system to produce antibodies. (The name antigen reflects its role in stimulating an immune response – antibody generating.)
attenuated. Weakened, less virulent. An attenuated virus is a live but weakened version of the virus. They are used to make vaccines that stimulate a strong immune response without causing disease.
cell culture. The artificial culture of cells under laboratory conditions. The cells are placed in a medium (often liquid) with the appropriate conditions, nutrients and chemicals to allow growth. Canine or monkey kidney derived cells can be cultured and used to grow influenza virus to produce a vaccine. Cell culture has the potential to rapidly develop and scale up production of vaccine virus in place of egg-based culture of the virus.
innate. Natural, inborn. The innate immune system is immunity that is naturally present and non-specific ie, it is not stimulated by exposure to an antigen. The innate immune system prevents infection by microorganisms in general eg, through the skin barrier, mucus secretion, stomach acid and non-specific white blood cells. It also aids in the production of a specific immune response.
mutated. Describes genetic material that has changed in amount or arrangement. A change in the sequence of a gene can be harmful or beneficial to an organism, and is a source of genetic variation. A mutation may enable a microorganism to evade detection by the immune system and cause disease, even though a person has been previously infected.
pandemic. The worldwide outbreak of a disease.
pathogen. An organism capable of causing a disease.
RNA (ribonucleic acid). A nucleic acid similar to DNA. In most organisms, RNA serves as a ‘read-out’ of the genetic information in DNA to facilitate various aspects of cell metabolism, particularly as a message for protein synthesis. However, in some viruses, including influenza, RNA is the primary genetic material instead of DNA, and is more prone to mutation than DNA. For more information see RNA (Nobelprize.org).
seed virus. The starter culture of virus for producing vaccine virus. An adapted virus from which larger quantities can be grown. Many of the seed viruses used for producing the flu vaccine are hybrids of pathogenic strains and a safe, fast growing strain. The resulting viruses are safer and easier to grow in quantity but still with the correct antigens to induce a protective immune response.
toxins. Substances, produced by microorganisms, which affect the functioning of another organism.
virulent. Able to cause severe illness or death. The virulence of an infective microorganism is measured as the proportion of people infected by the microorganism, who become severely ill or die.
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Posted February 2010.