Antibody and Antigen

Antibody and Antigen

Antibody and Antigen defination.

What is Antibodies?

Antibody and Antigen reaction.

Antibodies are compounds of proteins that are part of our immune system and provide protection to the body. Antibodies are also known as immunoglobulin (Ig). The simplest antibody (antibody) is Y-shaped, consisting of 4 polypeptide chains.

Of these 4 series, 2 are heavy chain (H) and two are called light chain (L). These two chains are connected to each other by a disulfide bond. The heavy chain contains 440 amino acids, while the lighter chain contains approximately 220 amino acids.

What is antigen?

Antibody and Antigen interaction

 Antigens are external elements that cause the immune system to produce antibodies. Antigens can be any of the bacteria, viruses, and fungi that spread the disease.

The antigens carried in the body through blood donation and the vaccine are called artificial antigens. Antigens react with their specific antibodies, and the antigen-antibody response is the basis of immunity.

 Difference of antibody and antigen

Antibody and Antigen diagram

Antibody and Antigen structure

Antibodies are made up of proteins, while antigens can be carbohydrates, lipids, or nucleic acids in addition to proteins. Antigens spread disease in the body, while antibodies remove the antigen and protect the body from disease.

Antibodies bind pathogens or antigens in outer space, and ensure the safety of the organism through three processes:

1. They can neutralize the pathogen or its toxic products by adhering to them and preventing infection or toxicity.

Antibody and Antigen complex

2. They may facilitate the capture of pathogens by phagocytic cells (opsonation).

3. They can activate the complement system, made up of a series of plasma proteins that help phagocytes to ingest and destroy bacteria. All pathogens and foreign particles bound to the antibodies will end up in the hands of phagocytes, which will destroy them. The complement system and phagocytes do not recognize the antigen; It is the antibodies that indicate their existence.

Innate and acquired immunity

The concept of innate immunity refers to the person with whom the person is born; The acquired, meanwhile, relates to that which is obtained through life and which, according to the way it is obtained, may be natural, when the person is suffering from a disease and makes antibodies; Or prosthetic, which is obtained by vaccination through vaccination or sera.

There are 5 types of antibodies.

1. Immunoglobulin M

2. Immunoglobulin G

3. Immunoglobulin E

4. Immunoglobulin D

5. Immunoglobulin A

There are 3 types of antigens:

1. Exogenous

2. Endogenous 

3. Autoantigens

The part of the antigen that reacts with the antibody is called the epitope, while the part of the antibody that connects to the epitope of the antigen is called the paratope..