Library · Physiology
Immune tolerance
Make it clearer
Immune tolerance is the reason your defense system does not attack you. Self antigens, the identity markers on your own cells, do not set off a response; foreign ones do.
That is learned before the cells go out into the world. Central tolerance happens where lymphocytes, the defense cells, mature: the thymus, an organ behind the breastbone, for T cells, and the bone marrow, the tissue inside your bones, for B cells. There they are put to the test: if a T cell sticks too tightly to something of your own, it is ordered to die by apoptosis, which is programmed cell death. That is called negative selection. It is an entrance exam that weeds out anyone who knows the place too well.
Later, on the outside, in the spleen and the lymph nodes, there is a second control network called peripheral tolerance. When that whole process fails, autoimmunity can show up, meaning the body ends up attacking itself.
In brief
Immune tolerance is the process by which self antigens do not trigger an immune response while foreign ones do.
Central tolerance happens in the thymus and bone marrow, where lymphocytes mature: a T cell that binds self with too high an affinity dies by apoptosis, a process called negative selection.
It is an entrance exam that weeds out anyone who knows the place too well.
Peripheral tolerance then acts in the spleen and lymph nodes; when the process fails, autoimmunity can appear.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingBiochemistry, Autoimmunity, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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