Glossary-Emerging Infection and Bioterrorism
Antibody - a specialized protein produced by the immune system that helps destroy disease-causing organisms. An antibody is a component of humoral immunity. Antibodies can be effective defenders against both bacteria and viruses. An antibody must be made specifically for each pathogen.
Biosafety level 3 (BSL-3) - a specially designed, high-containment laboratory facility used for work with infectious disease agents that can cause severe disease or are potentially lethal. The Centers for Disease Control and Prevention has established four levels of biosafety laboratory facility, with level 4 designated for use with the most hazardous agents.
CD4+ T cell - also known as a “helper” cell, a cell of the immune system that helps other immune system cells produce antibodies. CD4+ T cells are the cell type that are infected and destroyed by HIV.
Cell-mediated immunity - part of the immune system in which specific immune system cells, such as cytotoxic T cells, directly attack infected cells.
DNA - deoxyribonucleic acid, the chemical structure that contains the genetic information of an organism. The double helical structure is made of two strands consisting of deoxyribose and phosphate and is held together by bonds between purine and pyrimidine bases which project inward from two chains and form the genetic code.
Eukaryotes - organisms whose cells possess a membrane-bound structure called a nucleus that contains the genetic material (DNA).
Gene - a sequence of genetic material that provides the information to make a specific protein.
Heme– a small molecule that consists of an iron atom contained in the center of a large heterocyclic ring called a porphyrin. Heme is involved in many metabolic reactions that occur in the body and is sequestered by specific heme-binding proteins such as hemoglobin.
Humoral immunity - part of the immune system that provides immunity against disease-causing organisms in body fluids. The main functional unit of humoral immunity is an antibody.
Immune response – the body’s immune system response that defends against attacks from disease-causing agents. The body can produce two different immune responses –humoral immunity and cell-mediated immunity.
Immunogen - a substance that produces an immune response.
Immunogenicity- the ability of an antigen to elicit an immune response
MicroRNA-A short piece of single-stranded RNA about 21 to 23 bases in length that regulates the expression of genes. MicroRNAs function by binding to a matching piece of messenger RNA that encodes a protein and decreasing the production of that protein
Neuraminidase - a protein found on the surface of influenza viruses that is needed for the virus to exit the host cell and infect more cells. The action of this protein is inhibited by the class of antiviral drugs that includes the drug Tamiflu®. In the system using for naming influenza subtypes (H1N1, for example), the N stands for neuraminidase.
Pandemic - a disease occurring over a wide geographic area and affecting a very high proportion of the population. This term is often used to describe large outbreaks of influenza that occur worldwide and cause a high rate of death.
Pathogen - an organism that can cause disease, such as a bacterium or a virus.
Phase I clinical trial - the first stage in testing new drugs or vaccines in humans. Phase I trials are performed on small numbers of people and are designed primarily to test the safety of the new drug and to obtain information about dosages. Drugs that pass phase I trials go on to trials that determine effectiveness and possible side effects and are tested on larger groups of people. If safety and effectiveness are demonstrated, the drugs or vaccines may become approved as treatments.
Plasmid - a circular segment of DNA that encodes a separate set of genes than those present in chromosomes. Plasmids are most often found in bacteria, but they are also useful to scientists as vectors.
Reassortment – the recombination or mixing of the genetic material of viruses; may occur when two different influenza virus strains infect the same cell, resulting in the formation of a new influenza virus strain.
RNA - ribo nucleic acid, a chemical structure that is related to DNA, but has only one strand and a somewhat different chemical composition. RNA performs a variety of functions in the cell and can act as a messenger to carry the genetic code from the DNA to other parts of the cell. RNA can also serve as the genetic material of some viruses.
Vaccination - injection of a weakened or mild form of a disease-causing agent to produce immunity.
Vaccine - a preparation of killed or weakened microorganisms that is administered to produce or increase immunity to a particular disease.
Vector - a segment of genetic material that is used as a vehicle to introduce specific genes into cells.
Virus-like particle - a particle assembled from multiple copies of the capsid protein that, like a virus, can produce an immune response, but unlike a virus, is not infectious because it does not contain genetic material
Zoonosis - a disease that is transmitted from animals to humans. The incidence of zoonoses (plural) increases when humans exist in close contact with animals and when humans encounter animals in new geographical regions.