Glossary

• Active immunity = immunity which results from the production of antibodies by the immune system in response to an antigen
• Antibodies = proteins that bind to specific antigens on the surface of pathogens
• Antigen = toxin or other foreign substance which induces an immune response in the body
• Antigen-antibody complex = molecule formed from the binding of multiple antigens to antibodies, sometimes called an immune complex
• Antigen-presenting cell = a type of white blood cell that presents antigens to T cells
• Clonal selection = process by which the body produces B and T cells to respond to infections
• ELISA test = laboratory technique that detects certain antibodies, antigens and other substances in bodily fluid
• Endocytosis = process by which cells take in substances from outside of the cell by engulfing them in a vesicle
• Heavy and light chains = 2 chains per antibody molecule
• Herd immunity = when a large proportion of a population is vaccinated, so that the disease cannot spread
• HIV positive = damages cells in immune system weakening ability to fight infections
• Immunity = bodily power to resist an infectious disease
• Lymphocyte = type of white blood cell that helps the body's immune system to fight off pathogens
• Lysosome = A membrane-bound organelle that contains hydrolytic enzymes
• Memory cells = long-lived cells that can produce antibodies to a specific antigen
• Messenger RNA = carries the information from DNA to ribosomes
• Monoclonal antibodies = antibodies produced by a single clone of B cells
• Murein = a lipid component of the cell wall of bacteria
• Non-specific = generalized response to pathogen infections involving the use of several white blood cells and plasma proteins
• Passive immunity = provided when a person is given antibodies to a disease rather than producing them through their immune system
• Pathogen = a microorganism that causes disease in a host organism.
• Phagocyte = type of cell that has the ability to ingest and sometimes digest foreign particles
• Phagosome = vesicle formed around a particle engulfed by a phagocyte via phagocytosis
• Plasma cells = produce antibodies that are specific to a particular antigen
• Polyclonal antibodies = antibodies produced by many different B cells
• Retrovirus = virus that uses RNA as its genetic material
• Reverse transcriptase = enzyme that makes a copy of the RNA strand into a DNA strand
• Vaccine = dead/weakened forms of a pathogen injected into an organism to stimulate an immune response