| A | B |
|---|
| germ theory | theory that states that diseases are caused by microscopic particles called pathogens |
| pathogen | agent that causes disease |
| vector | organism, such as a mosquito or tick, that transfers pathogens from one host to another |
| immune system | body system that fights off infections |
| phagocyte | cell that destroys other cells by surrounding and engulfing them |
| T cell | white blood cell that matures in the thymus and destroys infected body cells by causing them to burst; also called a T-lymphocyte |
| B cell | white blood cell that matures in the bone marrow and produces antibodies that fight off infection; also called a B-lymphocyte |
| antibody | protein produced by B cells that aids in the destruction of pathogens |
| interferon | type of protein, produced by body cells, that prevents viruses from replicating in infected cells |
| passive immunity | immunity that occurs without the body undergoing an immune response |
| active immunity | immunity that occurs after the body responds to an antigen |
| inflammation | immune response that is characterized by swelling, redness, pain, and itching |
| antigen | protein marker that helps the immune system identify foreign particles |
| memory cell | specialized white blood cell that contributes to acquired immunity by acting quickly to a foreign substance that infected the body previously |
| cellular immunity | immune response that relies on T cells to destroy infected body cells |
| humoral immunity | immune response that relies on B cells to produce antibodies to help fight infection |
| tissue rejection | process by which a transplant recipient's immune system makes antibodies against the protein markers on the donor's tissue; can result in the destruction of the donor tissue |
| antiseptic | chemical, such as soap, vinegar, or rubbing alcohol, that destroys pathogens outside of the body |
| antibiotic resistance | process by which bacteria mutate so that they are no longer affected by an antibiotic |
| vaccine | substance that stimulates an immune response, producing acquired immunity without illness or infection |
| allergy | immune response that occurs when the body responds to a nondisease-causing antigen, such as pollen or animal dander |
| allergen | antigen that does not cause disease but still produces an immune response |
| anaphylaxis | severe allergic reaction that causes airways to tighten and blood vessels to leak |
| leukemia | cancer of the bone marrow that weakens the immune system by preventing white blood cells from maturing |
| opportunistic infection | infection caused by a pathogen that a healthy immune system would normally be able to fight off |
| human immunodeficiency virus (HIV) | virus that weakens the immune system by reproducing in and destroying T cells; causes AIDS |
| acquired immune deficiency syndrome (AIDS) | condition characterized by having several infections and very few T cells; caused by HIV |
