What are antibodies?

Antibodies, also known as immunoglobulins, are also composed of a cell division system, as well as some large molecular proteins brought about by bacteria and viruses. They are mainly found in human blood and body fluids, mainly on the surface of cell membranes. Antibodies mainly refer to the body's immune ability. Under the stimulation of antigens, some lymphocytes continue to proliferate and differentiate. The antibodies produced by different immunoglobulins are also different.

Antibodies are also distributed in tissue fluid or tissue cells. In daily life, they mainly bind specifically to antigens and activate some enzymes. The conditioning effect is the combination of antigens and antibodies with different cells. For example, placental antibodies protect the human body through the placenta.

Antibody refers to the immunoglobulin produced by the body's immune system under antigen stimulation, which is produced by plasma cells differentiated from B lymphocytes or memory cells and can specifically bind to the corresponding antigen. It is mainly distributed in serum, and also in tissue fluid and exocrine fluid.

Autoantibodies are antibodies directed against one's own tissues, organs, cells and cell components. The growth, development and survival of the human body are maintained by a complete autoimmune tolerance mechanism. The normal immune response has a protective defense effect, that is, it does not react to its own tissues and components. Once the integrity of self-tolerance is destroyed, the body regards its own tissues and components as "foreign bodies", and an autoimmune reaction occurs, producing autoantibodies. A normal human body may have low titers of autoantibodies in its blood without causing disease. However, if the titer of autoantibodies exceeds a certain level, it may cause damage to the body and induce disease.

Immunoglobulin (Ig) refers to a globulin that has antibody activity or a chemical structure similar to that of an antibody. Immunoglobulins are ubiquitously present in the blood, tissue fluids, and exocrine secretions of mammals and humans. There are five main types of immunoglobulins in the human body: IgM, IgA, IgG, IgD, and IgE. Antibodies are symmetrical structures of four polypeptide chains, two of which are relatively longer and have a larger molecular weight than the other two heavy chains (H chains); and two are relatively shorter and have a smaller molecular weight than the other two light chains (L chains). The chains are linked by disulfide bonds and non-covalent bonds to form a monomer molecule consisting of four polypeptide chains. There are two types of light chains: κ and λ, and five types of heavy chains: μ, δ, γ, ε, and α.

The above is what antibodies are. Its structure in daily life is also relatively special. It mainly binds to specific antigens and some cells and has a conditioning effect. The function of antibodies is mainly to combine with some new microorganisms and the first aid and prevention of diseases. Therefore, antibodies have more meanings for human immunoglobulins.