What is an antibody? Function, Structure, Autoimmune disease

What is an antibody?

Antibodies, also known as immunoglobulins, are glycoproteins produced naturally in response to invasive foreign particles (antigens) like microorganisms and viruses. As such, they play a critical role in defending the immune system against infection and disease.

Antigens recognized and bound by antibodies can be proteins such as receptors expressed on cancer cells, sugars on bacterial and viral cell surfaces, hormones, chemical compounds, or nucleic acid structures. The region of an antigen that interacts with an antibody is called the epitope.

Antibody

What is an antibody? Function, Structure, Autoimmune disease

It is in this way that an organism can identify “itself” from “non-self“. For example, the surface of bacterial cells has certain proteins and carbohydrates, which can be identified by the immune system. B lymphocytes, a special immune cell, create and release antibodies that attack invading bacteria. An antibody bound to a bacterium not only prevents it from completing normal processes but helps white blood cells eat the bacteria. These macrophages, as they are known, identify foods based on the rear end of the antibody.

In the blood, the antibodies make up about 20% of the total protein. This is a very significant amount. Although a single antibody may be very small, an organism must have many antibodies to combat the many types of antigens present in the system. Also, many of each type are needed. Many antibody molecules are often needed to identify and identify a large bacterium. Viruses, although smaller, are much more abundant and need equal amounts of antibodies to suffocate them.

. An antibody can also be called immunoglobulin, a term that describes a protein used in immune function. The most common antibody is immunoglobulin G (IgG) in mammals. While these organisms are also known to have immune systems, how they work is not entirely clear.

Antibody Function

Antibodies have three main functions:

  1. Antibodies are secreted into the blood and mucous membranes, where foreign substances such as pathogens and toxins bind and become activated (neutralization).
  2. Antibodies activate the complement system to destroy bacterial cells by lysis (drilling holes in the cell wall).
  3. Antibodies facilitate phagocytosis of foreign substances by phagocytic cells (opsonization).

Antibodies and the four key characteristics of the immune system.

  1. Antibody specificity: Antibodies accurately recognize toxins and pathogens.
  2. Diversity of Antibodies: Antibodies to a variety of antigens pre-exist in the body.
  3. Immune memory: we do not develop symptoms of measles
  4. Immune tolerance: cells and tissues do not attack normally.

Antibody structure

Above is a typical antibody. Note that the structure is made up of 4 different protein chains. 

What is an antibody? Function, Structure, Autoimmune disease

There are two heavy chains and two light chains. The two heavy chains are connected by a disulfide bond, which exists between two sulfide atoms present in the amino acids in each chain. Light chains bind to the sides of the heavy chain, through a series of non-covalent bonds and weak interactions.

Each chain is divided into two regions, the constant region, and the variable region. The constant region occurs directly from DNA and is the same in all antibody molecules of the same type. The variable region is the part of the antibody that changes according to the antigen present. B lymphocytes are in charge of a complex process that matches the variable region with the antigen, and then the mass produces the correct antibody.

It is the variable region that has a binding site, capable of binding to the antigen. The binding site is specific because it is designed to bind only the desired antigen. It does this by being as compatible as possible with the antigen. If the antigen is hydrophobic, so is the binding site. If the antigen is negatively charged, the binding site will have an optimal positive charge to help bind the antigen. Furthermore,

What is an antibody? Function, Structure, Autoimmune disease

The entire head shape of the antibody is specifically shaped to the antigen shape. This ensures that the antibody will be specific for the antigen. The antibody constant region can present itself in various forms and can be assembled into larger complexes with different forms.

Antibody action in autoimmune disease

In some cases, the antigen is so close to a molecule that the body produces that the immune system ends up attacking itself. This is known as an autoimmune disease. The immune system, when presented with an antigen, forms a defense. In these cases, the antigen is usually a protein. Protein is similar to a protein produced by the body. While the antibody formation system may be very specific, it cannot accurately identify two molecules that have the same shape. Therefore, even if the molecules are really “self”, you can end up attacking them.

Autoimmune diseases can be caused by a number of conditions. Some include viruses, such as HIV, that cause the immune system to target itself. Still other autoimmune diseases, such as certain forms of diabetes, can be caused by the immune system attacking the pancreas, an organ that secretes insulin. Some research has been done that can link this autoimmune reaction to the proteins found in animal products. While plant proteins have evolved on a completely different path, humans and farm animals share many of the same genes. This means that they produce many of the same proteins. If these proteins leak into the body without breaking down, they could be identified as an antigen.

By viewing this antigen, the immune system will create an antibody to contain it. These antibodies will be mass-produced and sent throughout the body to attack any protein in the same way. This can cause a serious problem for your body. Let’s say you just ate a hot dog. All parts of a pig and a cow are used to create hot dogs. It goes without saying that you will probably get proteins that originated from the animal’s pancreas, cartilage, or other organs. Because their proteins are so similar to yours, your body will start to have an immune reaction in the places where these proteins are present. This could be a major cause of diseases like diabetes, arthritis, and possibly even conditions like multiple sclerosis.

Use of antibodies in analytical techniques

An antibody can also be a very useful tool in the laboratory. Because an antibody is so specific and binds tightly under certain conditions, antibodies are used in various applications which are used to filter a solute from a solution. In column chromatography, they are used to bind to passing solute molecules. As the solution flows, the antibody retains the solute. A different solution, with a different pH, can be washed on the antibody medium, and the antibody will change shape and release the solute.

Another common use of an antibody in the lab is to detect certain substances. An antibody is linked to another protein, which is used to create a visible molecule. When the antibody is in the presence of the antigen, the antibody changes shape and activates the enzyme. This action creates visible molecules and can be detected visually or using a computer. This allows scientists to detect very small samples of a substance at a relatively low cost. This can be used to diagnose diseases, test products, and test the safety of consumer products.

An antibody can also be a very useful tool in the laboratory. Because an antibody is so specific and binds tightly under certain conditions, antibodies are used in various applications which are used to filter a solute from a solution. In column chromatography, they are used to bind to passing solute molecules. As the solution flows, the antibody retains the solute. A different solution, with a different pH, can be washed on the antibody medium, and the antibody will change shape and release the solute.

Another common use of an antibody in the lab is to detect certain substances. An antibody is linked to another protein, which is used to create a visible molecule. When the antibody is in the presence of the antigen, the antibody changes shape and activates the enzyme. This action creates visible molecules and can be detected visually or using a computer. This allows scientists to detect very small samples of a substance at a relatively low cost. This can be used to diagnose diseases, test products, and test the safety of consumer products.

What is an antibody? Function, Structure, Autoimmune disease

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What is an antibody? Function, Structure, Autoimmune disease

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