Basic information
Chinese name
immune system
Foreign name
immune system
kind
biology
catalogue
Basic functions of 1
2 composition structure
3 human body defense line
4 operating mechanism
5 Influencing factors
6 antibody production
7 historical evolution
8 adjustment measures
The basic function of folding and editing this paragraph
Immune system is an important system for the body to perform immune response and immune function. It consists of immune organs, immune cells and immune molecules. The immune system has the functions of recognizing and excluding antigenic foreign bodies, coordinating other systems of the body, and maintaining the internal environment stability and physiological balance of the body.
Immune system is the most effective weapon against pathogen invasion. We can find and remove foreign bodies, exogenous pathogenic microorganisms and other factors that cause internal environment fluctuations. However, its hyperfunction will cause harm to its own organs or tissues.
1. Identify and remove foreign invasive antigens, such as pathogenic microorganisms. This function of preventing the invasion of external pathogens and removing invasive pathogens and other harmful substances is called immune defense. Protect the human body from viruses, bacteria, pollutants and diseases.
2. Identify and eliminate mutated tumor cells, aging cells, dead cells or other harmful components in the body. This function of finding and eliminating "non-self" components in the body at any time is called immune surveillance. Metabolic waste and virus casualties and corpses left by immune cells in the war against viruses must be removed by immune cells.
3. Maintain the internal stability of the immune system through autoimmune tolerance and immune regulation. Repairing immune cells can repair damaged organs and tissues and restore their original functions. A healthy immune system is irreplaceable, but it may still fail because of continuous intake of unhealthy food.
Fold and edit the composition structure of this paragraph.
Folding immune organ
First, the immune organs
According to the difference of differentiation time and function, immune organs can be divided into central immune organs and peripheral immune organs. The former is the place where immune cells occur, differentiate and mature; The latter is the place where T and B lymphocytes settle and proliferate, and it is the main part of immune response.
Bone marrow:
Bone marrow is the main hematopoietic organ of human beings and other mammals, and it is also an important birthplace of various blood cells. Bone marrow contains pluripotent stem cells with strong differentiation potential, which can be differentiated into different hematopoietic progenitor cells under the action of some factors, and then differentiated into myeloid stem cells and lymphoid stem cells with different shapes and functions. Lymphatic stem cells differentiate into T cells and B cells through thymus, bursa of fabricius or bursa-like organs (bone marrow), and finally settle in peripheral immune organs. Mammalian and human B cells develop into mature B cells under the action of bone marrow microenvironment and hormone-like substances.
Thymus:
Thymus consists of thymic stromal cells (TSC) and thymocytes in reticular tissue, mononuclear macrophages from bone marrow, thymic dendritic cells and fibroblasts from connective tissue. Immature thymocytes are densely distributed in the thymus cortex, gradually migrate to the medullary region, and finally develop into mature single-positive thymocytes-T cells after double-negative cells and double-positive cells. In this process, macrophages (Mφ) and thymic dendritic cells distributed at the junction of cortex, cortex and medulla play an important role in the positive and negative selection of MHC on the surface of thymocytes.
1 T cells differentiate and mature;
2. Immunoregulation: it can regulate peripheral immune organs and immune cells;
3. Establishment and maintenance of autoimmune tolerance.
peripheral immune organ
Peripheral immune organs, also known as secondary immune organs, are the places where mature lymphocytes settle down, and they are also one of the important parts where these cells produce immune response under the stimulation of foreign antigens. Peripheral immune organs include lymph nodes, spleen, mucosa-associated lymphoid tissues, such as tonsils, appendix, intestinal lymph nodes, and many scattered lymphoid nodules and diffuse lymphoid tissues in submucosa of respiratory tract and digestive tract. These checkpoints are used to prevent the invasion of toxins and microorganisms. Studies have shown that there are a large number of lymph nodes in the cecum and tonsils, and these structures can assist the immune system.
tonsil
Tonsils are highly alert to intruders who enter the human body through the nose and mouth. Those who have their tonsils removed are more likely to suffer from strep throat and Hodgkin's disease. This proves that tonsils play a very important role in protecting upper respiratory tract.
Spleen:
1.The deposition sites of T cells and B cells;
2. Where the immune response occurs;
3. Synthesis of some bioactive substances;
Step 4 filter.
Lymph nodes:
Lymph nodes are a small battlefield with billions of white blood cells. When fighting is needed because of infection, foreign invaders and immune cells gather here, and lymph nodes will swell. As the excretory system of the whole army, lymph nodes shoulder the task of filtering lymph and taking away wastes such as viruses and bacteria. Lymphatic fluid in human body is about four times as much as blood. There are 500~600 lymph nodes in human body, which is a complete peripheral immune organ and widely exists in lymphatic channels in non-mucosal parts of the whole body. Lymph nodes have the following functions:
1.where T cells and B cells settle;
2. Where the immune response occurs;
3. Participate in lymphocyte recycling;
Step 4 filter.
Mucosal associated lymphoid tissue:
1. Intestinal associated lymphoid tissues: including Paget's lymph nodes (PP), lymphoid nodules, epithelial lymphocytes, lymphocytes diffused in lamina propria, etc.
⑴M cell: It is a special antigen transport cell. It exists in intestinal aggregated lymphoid nodules and paget aggregated lymphoid nodules.
⑵ Intraepithelial lymphocytes: They exist in small intestinal mucosa epithelium. About 40% is thymus-dependent and 60% is thymus-independent. It plays an important role in immune surveillance and cell-mediated mucosal immunity.
2. Nasal associated lymphoid tissues: including pharyngeal tonsil, palatal tonsil, lingual tonsil and other lymphoid tissues at the back of nose. Its main function is to resist the infection of airborne pathogenic microorganisms.
3. Bronchial associated lymphoid tissue: mainly distributed in bronchial epithelium of each leaf. Mainly b cells.
caecum
Cecum can help the maturation and development of B cells and the production of antibodies (IgA). It also acts as a traffic commander, producing molecules to direct white blood cells to various parts of the body. The cecum can also "notify" that white blood cells have intruders into the digestive tract. Cecum can not only help local immunity, but also help control the excessive immune response of antibodies. The most vulnerable part of pathogenic microorganisms is the oral cavity, and the intestine is connected with the oral cavity, so the immune function of the intestine is very important. Aggregation lymph node is an unwrapped lymphoid tissue in the lamina propria of intestinal mucosa, which is rich in B lymphocytes, macrophages and a small amount of T lymphocytes. Form a solid defense line against the invasion of pathogenic microorganisms into the intestine.
Folded immune cell
The constituent cells of innate immunity; Phagocytosis; Dendritic cells; NK cells; NKT cells; Eosinophils; Basophilic cells; Adaptive immunoreactive cells; T cells; B cells.
lymphocyte
(1) Lymphocyte homing: After leaving the central immune organ, mature lymphocytes often migrate through blood circulation and settle in specific areas of peripheral immune organs or tissues. For example, T cells settle in the subcortical area, and B cells settle in the superficial cortical area; Lymphocyte subsets with different functions can also selectively migrate to different lymphoid tissues.
⑵ Lymphocyte recycling: The process in which lymphocytes circulate repeatedly in blood, lymph and lymphoid organs or tissues.
Its significance lies in:
(1) makes the distribution of lymphocytes in vivo in peripheral immune organs and tissues more reasonable, which is helpful to enhance the immune function of the whole body;
⑵ Increasing the chance of contact with antigen is beneficial to the primary or secondary immune response;
(3) to integrate all immune organs and tissues of the body;
⑷ Transmitting immune information to the whole body is beneficial to the mobilization of immune cells and the migration of effector cells.
Lymphocyte classification: mainly including T cells and B cells.
1.b lymphocytes: They are derived from the lymphoid stem cells of mammalian bone marrow or bursa of fabricius of birds. Mature B cells are mainly located in lymph nodes of peripheral lymphoid organs. B cells account for about 20% of the total number of peripheral lymphocytes. Its main function is to produce antibodies to mediate humoral immune response and present soluble antigens.
Innate immune cell
Inherent immune cells: mainly include neutrophils, monocytes, dendritic cells, NK T cells, NK cells, mast cells, basophils, eosinophils, B- 1 cells, γσT cells, etc.
2. Function: Inherent immune cells mainly play a non-specific anti-infection role. They are defense cells formed in the long-term evolution process of the body, which can quickly produce an immune response to invading pathogens and also remove damaged, aged or distorted cells in the body.
Bone marrow erythrocytes and leukocytes
Bone marrow red blood cells and white blood cells are like soldiers in the immune system, and bone marrow is responsible for making these cells. Every second, 8 million blood cells die, and the same number of cells are produced here, so bone marrow is like a factory that makes soldiers.
Training ground: Thymus is just like training navy, army and air force to win wars. Thymus is a training factory for training various arms and services. Thymus distributes T cells to fight. In addition, the thymus gland also secretes hormones with immunomodulatory function.
Phagophage cell
When the pathogen penetrates the skin or mucous membrane and reaches the tissues in the body, phagocytes first escape from the capillaries and gather at the location of the pathogen. In most cases, pathogens are swallowed and killed. If they are not killed, they will reach nearby lymph nodes through lymphatic vessels, where phagocytes will further destroy them. This filtering effect of lymph nodes plays an important role in human immune defense ability. Generally, only a large number of virulent pathogens can invade organs such as blood flow without being completely blocked. But phagocytes in blood, liver, spleen or bone marrow will continue to devour and kill pathogens.
Taking pathogenic bacteria as an example, the process of phagocytosis and sterilization is divided into three stages, that is, phagocytic cells contact with pathogenic bacteria, phagocytosis of pathogenic bacteria, killing and destroying pathogenic bacteria. There are lysosomes in phagocytes, among which lysozyme, myeloperoxidase, lactoferrin, defensins, active oxygen substances and active nitrogen substances can kill bacteria, while protease, polysaccharide enzyme, nuclease and lipase can degrade bacteria. Finally, undigested bacterial residues will be discharged to the outside of phagocytes.
Bacteria are swallowed by phagocytes to form phagocytes; Lysosomes and phagocytes fuse into phagocytes; A variety of bactericidal substances and hydrolases in lysosomes kill and digest bacteria; Bacterial residues are excreted from cells.
Folded immune molecule
1. Membrane molecule: TCRBCR；; CD molecule; Adhesion molecule; MHC molecule; Cytokine receptor.
2. Secretory molecule: immunoglobulin; Supplement; Cytokine.
globulin
1. Concept: Globulins with antibody activity or similar chemical structure to antibodies are called immunoglobulins.
2. Classification:
⑴ Secretory globulin: It mainly exists in blood and symptom fluid and has multiple functions of antibodies.
⑵ Membrane globulin: It mainly constitutes the antigen receptor on B cell membrane.
3. Function:
Recognition and specific binding of (1) antigen; (2) activating complement; (3) Through placenta and mucosa; ⑷ Regulatory effect on immune response.
5. Binding to Fc receptors: IgG, IgA and IgE antibodies can bind to cells with corresponding receptors on their surfaces through their Fc segments, resulting in different biological effects: ① conditioning; ② Cytotoxicity mediated by antibody-dependent cells; ③ Mediate type I hypersensitivity.
supplement
1. Concept: Complement is a protein reaction system with precise regulation mechanism and an important immune effect amplification system in vivo. It widely exists in serum, tissue fluid and cell membrane surface, including more than 30 components.
2. Composition: (1) the intrinsic component of complement; (2) Complement regulatory protein; (3) Complement receptor.
3. Function: (1) bacteriolysis, toxin dissolution and cytotoxicity; (2) conditioning; ⑶ Immune adhesion; (4) Inflammatory mediators.
4. Activation mode: (1) classic mode; (2) MBL pathway; (3) detour route.
Cell molecule
1. Concept: Cell molecules are low molecular weight soluble protein produced by cells stimulated by immunogens, mitogens or other factors. They are biological information molecules, which have the functions of regulating innate and adaptive immune response, promoting hematopoiesis and stimulating cell activation, proliferation and differentiation.
2. Classification: ⑴ Interleukin; (2) chemokines; ⑶ Tumor necrosis factor; (4) Colony stimulating factor;
5. Interferon family: including IFN-α, IFN-β, IFN-ε, IFN-ω, IFN-κ and IFN-γ;
(6) Other cytokines: such as transforming growth factor-β and vascular endothelial growth factor.
adhesion molecule
1. Concept: Adhesion molecules are a general term for many molecules that mediate contact and combination between cells or between cells and extracellular matrix.
Classification: ① immunoglobulin superfamily; (2) Integrin family; (3) selectin family; (4) Mucin-like vascular address element; 5. Cadherin family. .
3. Common adhesion molecules: such as CD4, CD8, CD22, CD28, CTLA-4, ICOS, etc.
4. Function: (1) lymphocyte homing; ⑵ Leukocytes adhere to vascular endothelial cells during inflammation; ⑶ Auxiliary receptors and synergistic stimulation or inhibition signals in immune cell recognition.
Folded immune tissue
Skin and mucous membrane
1. Physical barrier: The skin and mucous membrane composed of dense epithelial cells have the function of mechanical barrier, which can prevent the invasion of pathogens.
2. Chemical barrier: Skin mucous membrane secretion contains a variety of bactericidal and bacteriostatic substances, such as gastric acid and saliva, which is a chemical barrier against pathogens.
3. Microbial barrier: The normal flora living in the skin mucosa resists pathogens by competing with pathogens or secreting some bactericidal substances.
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The blood-brain barrier is composed of pia mater, capillary wall of choroid plexus and glial membrane composed of astrocytes wrapped outside the wall. Its dense tissue structure can prevent pathogens and other macromolecules in blood from entering brain tissue and ventricle, and protect the central nervous system. Infants' blood-brain barrier is not perfect enough, and it is prone to central nervous system infection.
Placental barrier
It consists of basal decidua of maternal endometrium and fetal chorion. Under normal circumstances, it is difficult for pathogens and their toxic products infected by the mother to enter the fetus through the placental barrier. However, if the placental structure is not fully developed in the third month of pregnancy, the pathogens in the mother may invade the fetus through the placenta, interfere with its normal development, and cause deformity and even death. Drugs, like pathogens, may invade the fetus through the mother. Therefore, during pregnancy, especially in the early stage, we should try our best to prevent infection and try not to use or use drugs with great side effects.
Fold and edit this human defense line
The human body has three lines of defense:
1. The first line of defense
It is composed of skin and mucous membrane, which can not only prevent pathogens from invading human body, but also its secretions (such as lactic acid, fatty acid, gastric acid and enzyme) have bactericidal effect. There are cilia on the respiratory mucosa, which can remove foreign bodies.
2. The second line of defense
It is a bactericidal substance and phagocyte in body fluids.
These two lines of defense are natural defense functions gradually established by human beings in the process of evolution. The characteristic is that people are born with a defense function against a variety of pathogens instead of a specific pathogen, so it is called nonspecific immunity (also known as innate immunity). In most cases, these two lines of defense can prevent pathogens from invading the body.
3. The third line of defense
It is mainly composed of immune organs (thymus, lymph nodes and spleen, etc.). ) and immune cells (lymphocytes).
The third line of defense is the acquired defense function gradually established by the human body after birth, which is characterized by being born and only acting on specific pathogens or foreign bodies, so it is called specific immunity (also known as acquired immunity).
Operation mechanism of folding and editing this paragraph
Normal human body fluids, such as blood, tissue fluid and secretion fluid, contain many substances that can kill or inhibit pathogens. There are mainly complement, lysozyme, defensin, B- lysin, phagocytin, histone, normal opsonin and so on. The direct killing effect of these substances on pathogens is not as strong as that of phagocytes, and they often only cooperate with other antibacterial factors. For example, complement has only a weak bacteriostatic effect on Vibrio cholerae, but if complement is added to the complex of Vibrio cholerae and its specific antibody, the bacteriolytic reaction of Vibrio cholerae will soon occur.
When pathogenic microorganisms such as bacteria and viruses enter the human body, macrophages in the immune system first attack and engulf them in the stomach, and then break them into pieces through the action of enzymes. These microbial fragments appear on the surface of macrophages and become antigens, indicating that they have swallowed the invading bacteria and let T cells in the immune system know.
T cells and microbial fragments on the surface of macrophages, or microbial antigens, react immediately after meeting, just like the original locks and keys. At this time, macrophages will produce a lymphatic factor substance, and its biggest function is to activate T cells. Once T cells "wake up", they immediately send out an "alarm" to the whole immune system and report the news of "enemy" invasion. At this time, the immune system will dispatch a killer T lymphocyte, which will emit special B lymphocytes, and finally produce specific antibodies through B lymphocytes.
Killing T lymphocytes can find those infected human cells. Once found, they will destroy these infected cells like killers and prevent the further reproduction of pathogenic microorganisms.
When the infected cells are destroyed, the antibodies produced by B lymphocytes combine with the pathogenic microorganisms in the cells, making them lose their pathogenic effect.
Through the above series of complicated processes, the immune system finally defended our bodies.
When the first infection is suppressed, the immune system will record all the process tools of this pathogenic microorganism. If the human body is invaded by the same pathogenic microorganism again, the immune system has clearly known how to deal with it, and can respond easily, accurately and quickly to destroy the invading enemy.
Factors affecting the folding editing of this paragraph
In real life, when the work pressure is heavy, the psychological burden is heavy, and the mood is tense, people are often prone to get sick. What is the reason? Experts believe that this is the performance of the animal nervous system affecting the immune system. When the nervous system of animals is dysfunctional, the immune system will also be dysfunctional, which will lead to various intractable diseases.
For example, the normal activity of parasympathetic nerve can promote the secretion of saliva, gastric juice, intestinal juice, pancreatic juice and insulin. When parasympathetic nerve activity is weakened and continues:
1. The decrease of saliva can not completely eliminate harmful bacteria in the oral cavity, making chronic pharyngitis and oral ulcer difficult to cure.
2. The decrease of gastric juice can't kill Helicobacter pylori, which leads to chronic gastritis and gastric ulcer.
3. The decrease of intestinal fluid leads to the imbalance of intestinal flora, and colitis cannot be cured for a long time.
4. Decreased insulin secretion will lead to metabolic disorder, decreased immunity, and a large number of immune system diseases, such as AIDS, viral hepatitis and rheumatoid arthritis, in protein. Hypoinsulin can also lead to hyperglycemia, leading to hyperlipidemia and hypertension, accompanied by macrovascular diseases such as cardiovascular and cerebrovascular diseases, peripheral vascular diseases such as lower limb ulcers, toe ischemic pain (or necrosis), peripheral neuropathy, microangiopathy such as cataract, glaucoma, fundus diseases, retinopathy and glomerulosclerosis.
Therefore, normal animal nerve activity is very important to human body. If the symptoms of animal patients with neurological disorders are mild, taking some vitamin B 1 and oryzanol in moderation will have a certain regulatory effect.
Fold and edit this paragraph to produce antibodies.
Immune system and viral hepatitis
Everyone has his own natural defense system, which is the immune system. The immune system is sensitive to dangerous foreign substances, such as; Hepatitis virus, immune clearance. It is difficult for people with low immune function to get rid of the virus after contact with it, while people with good immune function rarely have chronic infection.
When discussing the immune system, two important terms are antigen and antibody. As you can imagine, antigens are foreign substances (such as hepatitis virus), and antibodies are soldiers in the immune system against antigens. When an antigen (such as hepatitis B antigen) infects the body, the immune system produces corresponding antibodies, namely hepatitis B antibodies. Antibodies bind to antigens and remove antigens from the body, so the human body is immune to hepatitis B virus.
Special hepatitis antigens and antibodies can be detected by special tests. These tests show that it is very important to carry out hepatitis serological examination in order to determine whether the liver-related abnormalities of patients are caused by viral hepatitis and what kind of hepatitis it is. [ 1]
The historical evolution of folding and editing this paragraph
1798: jenner tried vaccination and opened the door to immunology;
188 1- 1885: Pasteur made vaccines against cholera, anthrax and rabies;
1882: Mechnikov discovered the phagocytosis of macrophages;
1890: Belin tried to treat tetanus with passive immunotherapy;
Landsteiner found ABO blood type. The red cross was established;
190 1 year, Danish Belin invented diphtheria antitoxin and tetanus antitoxin;
1905, tuberculin invented by Koch, Germany;
1906: Pirquet found allergic reaction;
19 10: Dell discovered histamine and established antihistamine industry;
1922: Fleming discovered lysozyme and penicillin;
1944: Medawar tried skin transplantation (but the rejection was serious);
1947: Owen found that twins are not mutually exclusive;
195 1 year, South African Swiss sailors invented the yellow fever vaccine.
1954, Americans Enders, Weller and Robbins invented the polio vaccine;
1957: Interferon was found in isaacs and Lin Deman;
1959: Gowans discovered lymphatic circulation;
1960: lymphocyte modification;
196 1: the relationship between immune response and thyroid was found;
1966: T-B cell related reaction was found;
197 1: t cell inhibition was found;
1974: Jayne deduced the whole theoretical framework of immune control;
1975: milstein and Kohler made monoclonal antibodies;
1980: smallpox was officially declared extinct, but ...;
198 1: smallpox is gone, and AIDS is coming;
1984: T cell receptor structure was discovered;
1987: MHC structure type 1 was found.
Fold and edit this paragraph of adjustment measures
Immunity refers to the ability of the body to resist foreign invasion and maintain internal stability. The air is full of all kinds of microorganisms: bacteria, viruses, mycoplasma, chlamydia, fungi and so on. In the case of insufficient human immunity, everyone can become the pathogen of early shift. Although the human body will produce corresponding antibodies against different pathogens to resist reinfection, antibodies are specific and time-limited. For example, streptococcus antibodies can only protect the body from reinfection by streptococcus for a short time, and they cannot resist infection by other viruses. A person with low immunity can't resist the attack of cold virus at all, which is the real reason why he often catches a cold. Daily diet conditioning is the most ideal way to improve human immunity;
1, drink more yogurt: adhere to a balanced diet, if people have alcoholism, mental stress or unbalanced diet, it will weaken people's disease resistance. To correct this imbalance, we must rely on health-preserving bacteria, which are contained in yogurt.
2, drink more boiled water: this will keep the mucous membranes of the nasal cavity and mouth moist; Drinking more water can also make people refreshed and energetic. Studies have proved that boiled water has ideal physiological activity on human metabolism. Water is easily absorbed by human body through cell membrane, which enhances the activity of lactate dehydrogenase in human organs, thus effectively improving human body's disease resistance and immunity. Especially the first cup of warm water in the morning is particularly important.
3, eat more seafood: seafood is rich in iron, zinc, magnesium, selenium, copper and so on. Regular consumption can promote immune function.
4. Drink tea regularly: Scientists have found that tea contains a chemical called theanine. Because it can mobilize human immune cells to resist bacteria, fungi and viruses, and can improve human anti-infection ability by more than 5 times.
5. Drink some red wine: Most alcoholic beverages will inhibit the human immune system, but red wine, on the contrary, contains some antioxidants that are good for enhancing immune function and protecting the heart.
6, eat some animal liver: animal liver contains folic acid, selenium, zinc, magnesium, iron, copper, and vitamins B6, B 12. These substances help to promote immune function.
7. It is found that Cordyceps sinensis can effectively increase the number of cells and tissues in the immune system, promote antibody production, increase the number of phagocytes and killer cells, and reduce the function of some immune cells, which is the first choice to enhance human immunity.
8. Appropriate iron supplementation: Iron can enhance immunity; However, excessive iron intake is harmful to the health, and it should not exceed 45 mg per day.
9. Glutamine supplementation: it is an indispensable amino acid for human body and can be called one of the "sharp weapons" to strengthen the immune system. People who often catch cold or have loose bowels can take glutamine powder in fruit juice or cold boiled water.
10, arginine supplement: sea cucumber, eel, loach, cuttlefish, yam, black sesame, ginkgo, tofu skin, frozen tofu, sunflower seeds and hazelnut are all rich in this substance, and eating more will help enhance immunity.
research progress
For the first time, scientists have determined the exact conditions under which infection may trigger autoantibodies, which is the first time to find a loophole in the immune system.
Autoimmune diseases such as rheumatic fever and Guillain-Barre syndrome (the body produces antibodies to attack the heart and peripheral nerves respectively) may occur after the body has an immune response to specific infectious microorganisms (antigens). But we haven't been able to explain why autoimmunity occurs, and we don't know why the body can't avoid this situation.
Our immune cells (such as effector B cells that produce antibodies) can correctly identify themselves from the beginning and avoid attacking themselves. Generally speaking, this formation process is reliable, stable and controllable. However, when the body resists disease or infection, B cells will go through more complicated developmental stages.
In order to cope with countless microorganisms introduced into the body, B cells have evolved a special ability to randomly mutate their antibody genes until one of the antibodies can effectively bind the invaders. At this time, "successful" B cells continue to proliferate, allowing these new antibodies to flood the entire immune system. In the special environment of lymphatic system, this kind of "high affinity antibody" is produced very quickly. Most of the time, the hair growth center works normally, helping us to resist diseases and build an arsenal to deal with future infections. However, sometimes there are problems. Antibodies (or antigens) used to resist intruders can also self-match, leading to autoimmune attacks.
In order to study the mechanism of autoimmunity, researchers developed a complex mouse model. It is found that when antigens flood the whole immune system, B cells that can produce autoantibodies will be eliminated to avoid autoimmune reactions. On the contrary, when the target antigen only exists in local tissues or organs far from the germinal center, B cells that can produce autoantibodies can survive and produce autoantibodies with high affinity.