Fever, also known as pyrexia, is an abnormal elevation of body temperature.
That heating boosts our immunity by speeding disease-fighting cells to an infection. A fever may be (mostly) good for us, whether we're babies, teens or adults. A new study shows how it speeds infection-fighting cells to where they'll do the body good.
When a person is exposed to an antigen for the first time the immune reaction is called the primary response. The appearance of protective antibodies is delayed for 3-6 days while naive B cells multiply and differentiate. As the plasma cells begin secreting antibody, the antibody titer begins to rise.
A pyrogen is a substance (infectious organisms or their product toxins or cytokines) that provokes fever. Exogenous pyrogens are substances, which originate outside the body and which are capable of inducing interleukins.
You get a fever because your body is trying to kill the virus or bacteria that caused the infection. Most of those bacteria and viruses do well when your body is at your normal temperature. But if you have a fever, it is harder for them to survive. Fever also activates your body's immune system.
What are the benefits of a fever? Fever is not an illness. It is a symptom, or sign, that your body is fighting an illness or infection. Fever stimulates the body's defenses, sending white blood cells and other "fighter" cells to fight and destroy the cause of the infection.
(AN-tih-jen) Any substance that causes the body to make an immune response against that substance. Antigens include toxins, chemicals, bacteria, viruses, or other substances that come from outside the body. Body tissues and cells, including cancer cells, also have antigens on them that can cause an immune response.
All adaptive immune responses develop in steps, consisting of: antigen recognition; activation of specific lymphocytes to proliferate and differentiate into effector and memory cells; elimination of the antigen; and decline of the response, with memory cells being the long-lived survivors.
The first contact that an organism has with a particular antigen will result in the production of effector T and B cells which are activated cells that defend against the pathogen. The production of these effector cells as a result of the first-time exposure is called a primary immune response.
Fever develops when the hypothalamus is set to a higher-than-normal temperature. This resetting of the hypothalamus is usually caused by small molecules called pyrogens in the blood. Pyrogens can come from outside the body (external) or can be produced inside the body (internal).
Some pyrogens are produced by body tissue; many pathogens also produce pyrogens. When the hypothalamus detects them, it tells the body to generate and retain more heat, thus producing a fever. Children typically get higher and quicker fevers, reflecting the effects of the pyrogens upon an inexperienced immune system.
A fever fights infection by helping immune cells to crawl along blood-vessel walls to attack invading microbes.