Uses of immunoglobulin

The immune system is one of the eight systems in our human body and plays a very important role. When our body is invaded or infected, our immune cells are activated and then they are responsible for killing bacteria and eliminating viruses. Immunoglobulin is a globulin with immune ability. We all know that AIDS is a virus that directly attacks immune cells, reducing the body's resistance and eventually causing bacterial infection and death. So how exactly do immunoglobulins work?

Immunoglobulin: refers to a globulin that has antibody (Ab) activity or chemical structure and is similar to antibody molecules. Immunoglobulins are tetrapeptide chains composed of two identical light chains and two identical heavy chains connected by interchain disulfide bonds. Immunoglobulins are divided into five categories, namely immunoglobulin G, immunoglobulin A, immunoglobulin M (), immunoglobulin D and immunoglobulin E.

Immunoglobulins can be divided into antibodies and membrane immunoglobulins. Antibodies are mainly present in serum, and can also be found in other body fluids and exocrine fluids. Their main function is to specifically bind to antigens. Membrane immunoglobulins are antigen receptors on the B cell membrane that can specifically recognize antigen molecules. In the body, antibodies and antigens can directly exert their effects after binding, such as antitoxins can neutralize exotoxins, virus neutralizing antibodies can prevent viruses from infecting target cells, and secretory IgA can inhibit bacteria from adhering to host cells. In vitro, aggregation and precipitation may occur after antibodies bind to antigens. Immunoglobulins can activate complement and bind to the Ac receptor on the cell surface (Ac is the crystalline fragment. Papain hydrolysis of IgG molecules can produce two Fabs and an Ac segment. This fragment can interact with effector molecules and effector cells, but cannot bind to antigens.) to exhibit different biological effects, such as conditioning, antibody-dependent cell-mediated cytotoxicity, and mediating type I hypersensitivity reactions; they pass through the placenta and mucosa. In humans, IgG is the only type of Cg that can pass through the placenta. The transfer of maternal IgG to the fetus through the placenta is an important natural passive immunity and is of great significance for neonatal anti-infection. Secretory IgA can pass through the digestive and respiratory mucosa and is the main factor in the body's local mucosal immunity. In addition, antibodies have both positive and negative regulatory effects on immune responses.

Antibodies are a type of globulin with immune function that can specifically bind to corresponding antigens and is synthesized and secreted by the body's immune cells after B cells differentiate and mature into plasma cells after being activated by antigens. Antibody is a concept of biological function, while immunoglobulin is a concept of chemical structure. The chemical basis of all antibodies is immunoglobulin, but not all immunoglobulins have antibody activity.