Acquired immunity |
Review about a natural immunity
If we eat harmful food to the body, we will vomit, or have diarrhea and try to eliminate the deleterious material from the body.
If a harmful thing enters from a nose, we sneeze or have a sputum, and try to eliminate harmful things, and prevent them from going inside the body.
A neutrophils which appeared in blood and a tissue and a macrophage and NK cell which are in a tissue defend for bacteria, mold or a virus. |
| Bacteria and viruses which passed through this natural immunity are got rid of by the mechanism called the acquired immunity that a B cell and a T cell play an active part. |
B cell and T cell are mainly in the place called a lymphatic tissue |
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The lymph system includes all structures which carry out the circulation and production of the lymphocyte (B cell and T cell) such as the lymphatic tissue associated with spleen, thymus, bonne marrow, and the gastrointestinal tract. The tonsil is included as well. |
| It is the lymph node which we touch with a hard lump under a jaw, on a neck and the root of a thigh. |
The lymphatic system has connected lymph node etc. with a pipe called a lymph vessel.
There is no pump like the heart unlike a blood vessel.
Lymph moves by contraction of the surrounding muscular tissues.
In addition, a valve as well as a vein is in a pipe, and it has the structure which lymph can move forward.
Lymph flows into the subclavian vein on the right and the left. |
・The function of a lymphatic tissue
１）The liquid between cells is called tissue fluid. Work to lade will be done if this tissue fluid becomes full. Surplus liquid flows into the subclavian vein on the right and the left.
２）The lymph vessel distributed along the surface of the gastrointestinal tract carries the lipid absorbed by the small intestine in a vein.
３）A B cell and a T cell and so on related to immunity are made. |
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A B cell cannot be distinguished from a T cell to the eye.
胸管：thoracic duct,扁桃腺：tonsil,胸腺：thymus,秘蔵：spleen,リンパ節：lympho node, リンパ管：lymph vesselB細胞：B cell,T細胞 ：T cell,形質細胞：plasma cell ,リンパ節組織system of lymph node
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Let’s study about a plasma cell later.
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扁桃腺：amygdala、胸腺：thymic gland、脾臓：spleen、リンパ節：lymphonodus、リンパ管：lymphatic vessel、胸管：thoracic lymph duct
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A B cell and a T cell patrol between a lymphatic tissue and blood.
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静脈：vein,胸管：thoracic duct
A B cell and a T cell go into a subclavian vein from a thick lymph vessel called a thoracic duct, and drift the inside of blood. And they return to a lymphatic vessel again and arrive at the lymph node of a set place. This movement of the repetition seems to be a patrol.
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静脈：vein,胸管：thoracic duct
When a virus invades around a throat, and when the left arm is injured with a knife like an animation, the lymphocyte under patrol finds the invaded pathogen at the lymph node nearby.
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| A nearby B cell and T cell change the course always patrolled, and gather at the lymph node in which a pathogen is. |
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| Let's study what happens when virus go in the body. |
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A virus tries to enter our cell.
It is because it increases using the mechanism in our living cell.
It cannot increase company outside the cell. |
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ウイルス：virus、樹状細胞：dendritic cell、体細胞：somatic cell |
ウイルス：virus,樹状細胞： dendritic cell、体細胞：somatic cell
ヘルパーT細胞：Helper T cell、キラーT細胞：Killer T cell
B細胞：B cell、形質細胞： Plasma cell リンパ節：Lymph node
A virus approached a cell as you see in the animation.
The dendritic cell in every place eats a virus as a macrophage does.
(Compared with a macrophage, the power to eat is weak.) |
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| This cytokine cheers up a sleeping killer T cell. |
The killer T cell which came out of the lymph node adheres to the cell damaged by the virus, and defeats this cell.
A virus dies with the cell as well. |
| How about a B cell? |
| The human being has all antibodies for the thing which can become every antigen in the natural world. |
| Strange, isn’t it? It is one of aspects that a human being is great. |
| There is an antibody in the cell surface of a B cell. |
| As you see in the animation, the antibody which came out from a B cell considers a virus as an antigen, and defeats a virus. |
A B cell also catches a virus. A helper T cell adheres to it. A different cytokine comes out from here.
This acts on a B cell, and a B cell is divided and increases. It changes to a plasma cell here.
A plasma cell produces an antibody in large numbers, and a virus is defeated by this.
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| What is an antibody? |
Usually, foreign pathogens such as bacteria and a virus etc. and proteins which enter the body by artificial injection etc. become antigens.
There is a case that an ingredient constituting our body becomes an antigen and the immune response happens. This is the disease called autoimmune disease. |
●What about bacteria?
Many bacteria cannot enter our cell. Bacteria do not increase in a cell as a virus does, but a cell can be damaged by the virulence of bacteria.
The damaged cell by a killer T cell will be processed then by the method same as a virus.
A B cell will play an active role as well.
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Please click here when you want to learn about the B cell more preceisely. |
As for a T cell, let’ study next time. |
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