Antigens and Antibodies: How They Work in the Immune System

There are different types of antibodies. Their types are explained in detail further. The specific type of antibody tells about its function and role in the body. The word Ig is used before the name of every type of antibody, here Ig is used for immunoglobulin, while the word after it indicates a special type of antibody.

IgM:
This antibody starts forming after the germs enter the body. It is made up of five types of units, due to which its quantity increases. This antibody sticks firmly to its target. IgM antibodies are important for the primary stage of infection. These types of antibodies sometimes start forming even when the infection (such as herpes) starts again. Apart from this, sometimes these antibodies start forming in the body even after a disease recurs. 

IgA:
This type of antibodies are present in mucus, saliva, tears and mother's milk. These protect against germs in the mucous membrane and provide passive immunity to the newborn. 

IgD:
This is important for the initial process of the immune system. It is found in B cells and acts as a receptor. This type of antibody is not well understood and more research is being done on its functions. 

IgG:
This is a primary and secondary response antibody, which is found in blood plasma. This antibody reaches the newborn through the placenta and provides passive immunity. This antibody provides long-term immunity after vaccination and infection. 

IgE:
This antibody is responsible for allergic reactions. It is usually found in the lungs, skin and mucous membranes. When IgE binds to germs, it triggers a histamine reaction. Allergy symptoms start appearing in the histamine reaction. These antibodies also help protect the body from parasitic worms.

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As soon as external antigens enter your body, the immune system becomes active. During this, chemicals signal different parts of the immune system to become active. In this process, the virus first gets mixed in a cell called B cells. After this, B cells produce antibodies compatible with the antigen. After being formed, antibodies stick to the virus and after this the process of destroying the antigen begins. During this, T cells get the order to damage the antigens marked by antibodies. This destroys the antigens.

Antibodies are made by special types of white blood cells. These special types of white blood cells are also called B cells or B lymphocytes. Antigens bind to the surface of B cells and stimulate them, causing the B cell to divide into groups of identical cells (clones). Such fully developed B cells are also called plasma cells and these cells secrete millions of antibodies into the lymph nodes and blood circulation. As the antibodies start circulating in the blood, they start destroying and reducing the antigen.

The causes of low antibodies vary depending on its type. Which are as follows:

IgG deficiency:
The causes of IgG deficiency are divided into two parts, such as primary and other causes. Researchers have not been able to find out the primary causes of IgG, but genetics is considered important in it. Age, nutritional deficiency, medicines such as chemotherapy and HIV infection are considered to be other reasons for low IgG. In this, the person shows symptoms of ear infection, pneumonia, bronchitis, sinus and other respiratory tract infections. 

IgM deficiency:
The causes of IgM deficiency have not yet been known. Many factors are responsible for its deficiency. Cases of such problems have been seen in some families, but there is no information about which specific type of genes cause this problem. This condition is seen in people who have abnormalities in their chromosomes. 

IgA deficiency:
IgA deficiency is the most common type of immunodeficiency syndrome. Most people appear healthy when they have IgA deficiency. But due to IgA deficiency, there is a high possibility of infection, allergy, diarrhea and autoimmune diseases. The cause of its deficiency is not known. In this condition, there is a complete lack of IgA in the person's body. IgA plays an important role in the respiratory system, gastrointestinal tract, mucosal immunity and protection from infection. 

IgE deficiency:
IgE deficiency is mainly considered to be associated with certain types of syndromes such as excess of IgM and others. Apart from this, this condition also arises due to some microorganisms. 

IgD deficiency:
The causes of IgD deficiency are not known. Many types of genetic reasons are found to be related to it.

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Antibodies are also called immunoglobulins. It is a protein produced by the body, which helps fight external harmful elements called antigens. After antigens enter the body, they stimulate the immune system to produce antibodies. Antibodies attach to the antigen or bind the antigen. Along with this, antibodies also neutralize antigens. A healthy adult has thousands of antibodies in his body.

Antibodies are Y-shaped proteins secreted from special types of white blood cells. They have the ability to recognize germs like viruses and bacteria. Thousands of different types of antibodies present in a person's body work to protect against special types of germs. For example, out of thousands of antibodies present in the body, only the antibody that destroys chicken pox damages and destroys its virus.

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Antigens (germ) elements are capable of stimulating the immune system, especially activating lymphocytes. Lymphocytes are infection-fighting white blood cells present in the body. Antigens are usually identified in two forms, which include external antigens (heteroantigens/ foreign antigens) and antigens formed inside the body (autoantigens/ self antigens).

Antigens can be bacteria, viruses or chemicals. External antigens are germs outside the body. Whereas autoantigens start forming inside the person's body on their own. Normally the body destroys the germs on its own, but in case of autoimmune disorder, such auto antibodies start forming in the body of the person, which mistakenly start reacting on the organs and tissues of the person.

The types of antigens are divided into the following two parts based on the origin of the antigen and the effect of the immune system. Types of antigens based on origin

Extrogenous antigens:
Such antigens enter the body and start moving with the blood and body fluids. 

Endogenous antigens:
In this, the cells of the body make antigens. 

Auto antigens:
Autoantigens are usually a complex form of a normal protein or several proteins, which are found in patients suffering from a specific autoimmune disease. In normal conditions, these antigens are not the target of the immune system, but this happens due to genetic and other external factors. Antigens based on the effect of the immune systemImmunogen.

Complete antigen:
In this, the antigens react on the immune system itself. 

Haptens/ Incomplete antigens:
Such antigens require a medium to react to the immune system.

The antigen enters the body and stimulates the immune system. After this, the reaction of the immune system starts.