Science News for Students: Explainer - What are Antibodies?

The body makes this chemical ammo to fight foreign invaders — now and later.


Article includes Power Words

allergen: A substance that causes an allergic reaction.

antibodies: Any of a large number of proteins that the body produces from B cells and releases as part of a so-called immune response. The production of antibodies is triggered when the body encounters an antigen, some foreign material. Antibodies then lock onto antigens as a first step in disabling the germs or other foreign substances that were the source of those antigens.

bacteria: (singular: bacterium) Single-celled organisms. These dwell nearly everywhere on Earth, from the bottom of the sea to inside other living organisms (such as plants and animals). Bacteria are one of the three domains of life on Earth.

cell: The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells. Most organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell.

develop: To emerge or to make come into being, either naturally or through human intervention, such as by manufacturing.

germ: Any one-celled microorganism, such as a bacterium or fungal species, or a virus particle. Some germs cause disease. Others can promote the health of more complex organisms, including birds and mammals. The health effects of most germs, however, remain unknown.

host: (in biology and medicine) The organism (or environment) in which some other thing resides. Humans may be a temporary host for food-poisoning germs or other infective agents. (v.) The act of providing a home or environment for something.

immune: (adj.) Having to do with the immunity. (v.) Able to ward off a particular infection. Alternatively, this term can be used to mean an organism shows no impacts from exposure to a particular poison or process. More generally, the term may signal that something cannot be hurt by a particular drug, disease or chemical.

immune system: The collection of cells and their responses that help the body fight off infections and deal with foreign substances that may provoke allergies.

infection: (adj. infectious) A disease that can spread from one organism to another. It’s usually caused by some type of germ.

influenza: (also known as flu) A highly contagious viral infection of the respiratory passages causing fever and severe aching. It often occurs as an epidemic.

measles: A highly contagious disease, typically striking children. Symptoms include a characteristic rash across the body, headaches, runny nose, and coughing. Some people also develop pinkeye, a swelling of the brain (which can cause brain damage) and pneumonia. Both of the latter two complications can lead to death. Fortunately, since the middle 1960s there has been a vaccine to dramatically cut the risk of infection.

microbe: Short for microorganism. A living thing that is too small to see with the unaided eye, including bacteria, some fungi and many other organisms such as amoebas. Most consist of a single cell.

mumps: A highly contagious childhood viral disease characterized visually by swollen cheeks and a puffy jaw due a swelling of the salivary glands. It causes flu-like symptoms, including fever, muscle aches, headaches and being very tired. It’s spread as influenza is, by sneezing, coughing or touching something contaminated with the virus, such as a patient’s hands, drinking glass or spoon. In rare cases, the disease can inflame the brain, spinal cord or other tissues or cause deafness.

pollen: Powdery grains released by the male parts of flowers that can fertilize the female tissue to make a seed. Pollinating insects, such as bees, often pick up pollen that will later be eaten.

protein: A compound made from one or more long chains of amino acids. Proteins are an essential part of all living organisms. They form the basis of living cells, muscle and tissues; they also do the work inside of cells. Among the better-known, stand-alone proteins are the hemoglobin (in blood) and the antibodies (also in blood) that attempt to fight infections. Medicines frequently work by latching onto proteins.

vaccine: (v. vaccinate) A biological mixture that resembles a disease-causing agent. It is given to help the body create immunity to a particular disease. The injections used to administer most vaccines are known as vaccinations.

virus: Tiny infectious particles consisting of RNA or DNA surrounded by protein. Viruses can reproduce only by injecting their genetic material into the cells of living creatures. Although scientists frequently refer to viruses as live or dead, in fact no virus is truly alive. It doesn’t eat like animals do, or make its own food the way plants do. It must hijack the cellular machinery of a living cell in order to survive.

Anatomy & Physiology, Health & Medicine
K-6, Middle School

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