Antibodies, also called immunoglobulins (Ig), are protein structures found in blood plasma. They act against invading organisms such as bacteria and viruses.
Occupation
The main function of antibodies is to body defense, which act directly against invading microorganisms that can cause various infections and diseases. In this way, they neutralize extracellular parasite toxins.
Production and Action
At proteins of antibodies are produced and secreted by a specific white blood cell, called a lymphocyte B (plasma cells).
Once they recognize the antigen that threatens the body, they readily produce antibodies to attack the invading agent.
In this way, they prevent the invading agent from multiplying by inhibiting the action of the released toxins, collaborating with the body's immune system.
Want to know more? Read more about the topic:
- Lymphocytes
- Leukocytes
- Immune system
Structure
Antibody structure
The structure of antibodies is formed by four polypeptide chains composed of amino acids. Two of them are bigger and heavier (P) and two are smaller and lighter (L). These chains are connected by disulfide bridges.
Types
Antibody Isotypes
There are several isotypes of antibodies, which vary according to the function and type of chain they present:
- IgG (Immunoglobulin G): very important in inflammatory processes as it neutralizes toxins released by external agents. IgG is present in lymph and blood and is divided into subclasses: IgG1, IgG2, IgG3 and IgG4. Note that Immunoglobulin G is the only one that crosses the placenta.
- IgE (Immunoglobulin E): important isotype of antibody that acts on allergic processes, verminosis and protozoa. Present in blood serum, IgE is found on the surface of basophils and mast cells.
- IgD(Immunoglobulin D): has the function of activating cells that protect the body. IgD is found in blood and its functions are still being defined and studied by several researchers.
- IgM (Immunoglobulin M): found in the intravascular environment, this type of antibody works as an antigen receptor. So when the body has high levels of IgM, it indicates a recent infection. Because it is large, this type does not cross the placenta.
- IgA (Immunoglobulin A): present in body secretions (saliva, sweat, tears, gastric juice, etc.), IgA has the function of protecting the body through the mucous membranes. That is, it prevents the invading agent from penetrating the epithelium. This type is subdivided into two classes: IgA1 and IgA2.
antigens
Antigens are the invading agents that cause various health problems in the body. They can be bacteria, fungi, viruses, etc.
Want to know more about it? Read the articles:
- Diseases Caused by Bacteria
- Diseases caused by Protozoa
- STD-Sexually Transmitted Diseases
