The role of immunoglobulins

We all have immunoglobulins in our bodies. The presence of immunoglobulins can help us phagocytize some pathogenic cells and protect our bodies from being invaded by pathogens. In addition to phagocytic cells, immunoglobulins can also help people clear necrotic cells in the human body, thereby maintaining the body's metabolism and normal blood circulation. The role of immunoglobulin is very important for people.

If there is any problem with the immunoglobulin in the human body, the immunity will easily decline. In this case, the health of the human body will be seriously threatened. This is something that everyone should pay attention to. Immunoglobulins are very important.

1. Function of immunoglobulin V region

It mainly recognizes and binds to antigens specifically. Since Ig has monomers, dimers and pentamers, the number of antigen epitopes it binds is also different. The number of Ig-binding antigen epitopes is called the antigen-binding valency.

2. Function of immunoglobulin C region

(1) Activation of complement

After IgG1-3 and IgM bind to the corresponding antigen, the complement binding sites in their CH2/CH3 functional regions may be exposed due to conformational changes, leading to activation of the conventional complement pathway. IgG4, IgA and IgE cannot activate the traditional complement pathway after binding to antigens, but their aggregates can activate the alternative complement pathway.

(2) Cell tropism

IgG and IgE antibodies have cytotropic properties and can bind to cells with corresponding receptors on their surfaces through their Fc segments, producing different biological effects.

(3) Regulation effect

After IgG binds to particulate antigens such as bacteria, it can promote the phagocytosis of particulate antigens such as bacteria by phagocytes through the binding of its Fc segment to the corresponding IgGFc receptors on the surface of macrophages and neutrophils. This is the opsonophagocytic effect of antibodies.

(4) Antibody-dependent cell-mediated cytotoxicity (ADCC)

After IgG binds to tumor or virus-infected target cells, it can bind to the corresponding IgGFc receptors on the surface of NK cells, macrophages and neutrophils through its Fc segment, thereby enhancing the killing and destructive effects of NK cells and triggered macrophages on target cells, thus producing the ADCC effect.

(5) Mediating type I hypersensitivity reactions

IgE is a cell-tropic antibody that can bind to the corresponding IgEFc receptors on the surface of mast cells and alkaliphilic granulocytes through its Fc segment, thus putting the above immune cells into a sensitized state. When the same allergen enters the body again and binds to the specific IgE on the surface of sensitized target cells, it can degranulate and release biologically active mediators such as histamine, causing type I hypersensitivity reaction.

The above is an introduction to the role of immunoglobulin. I believe that after reading it, you will have a better understanding of this knowledge. If we feel any discomfort in our lives, we should go to a regular hospital for examination and treatment in time. A low level of immunoglobulin can be very dangerous.