Structure
Immune system
The cells, tissues and molecules that defend the body against infection.
The fast, built-in first line of defense. Toll-like receptors recognize features shared by many microbes.Source: Lemaitre et al., 1996Source: Medzhitov et al., 1997Source: Poltorak et al., 1998
Structure
The cells, tissues and molecules that defend the body against infection.
Structure
A cell type identified in 1973 that captures antigens and presents them to T cells, linking innate and adaptive immunity.
Organism or group
Small single-celled organisms without a nucleus, found almost everywhere on Earth. Most bacteria in the human body are harmless, and some are helpful.
The explanations on this page are our own summaries of these sources. Follow a link to read the original; if anything here disagrees with it, the original wins. How we choose and check sources.
Lemaitre B, Nicolas E, Michaut L, et al. (1996). Cell 86:973-983.
Medzhitov R, Preston-Hurlburt P, Janeway CA Jr (1997). Nature 388:394-397.
Poltorak A, He X, Smirnova I, et al. (1998). Science 282:2085-2088.