Complement

Complement is a group of nine plasma factors present in the blood in the form of inactive proenzymes that activate each other in a certain sequence.

Complement plays an important role in the immune system. It participates in the binding reactions of antibodies to antigens foreign to the body. Complement promotes destruction (lysis), agglutination and opsonization of foreign cells.

During the antigen-antibody reaction, which is accompanied by complement activation, the accumulation of phagocytes may also occur, clearing the body of foreign cells.

Thus, complement is involved in many processes aimed at recognizing and destroying infectious agents, providing an important mechanism of innate and acquired immunity.

Complement is a group of nine plasma factors present in the blood in the form of inactive proenzymes that activate each other in a certain sequence.

Complement is involved in the following processes:

1. Reactions of binding by antibodies to antigens that have invaded the body.

2. Promotes destruction (lysis), agglutination and opsonization of foreign cells.

3. During the accompanying antigen-antibody reaction, the accumulation of phagocytes may also occur, clearing the body of cells foreign to it.

Complement plays an important role in the immune system, participating in the humoral immune response. Its activation is part of a cascade of reactions aimed at destroying foreign pathogens.

Complement is a group of nine specific proteins produced by the liver that play an important role in the body's immune system. It consists of several components, including C1, C2, C3, C4, C5, C6, C7, C8, and C9. These components are proenzymes, that is, inactive forms of proteins. Each of these components activates the next one so that they work together to protect the body from infections and other pathogenic influences.

Complement plays an important role in protecting the body from pathogens and foreign objects. It is responsible for the destruction, agglutination and opsonization (attachment) of foreign particles. When a person becomes infected, it causes immune cells to activate and produce a certain amount of complement. If the amount of complement is high enough and all nine components are fully active at the same time, then the person is considered to be “cured” of the infection because their immune system has learned to use complement to fight pathogens.

There are several ways complement can be activated, including the binding of proteins to an allergen, the formation of agglutinins when two allergens come together, or an immune complex reaction between an immunoglobulin (Ig) and an antigen (Ag). Complement activation can be suppressed with certain medications. For example, the active medical use of penicillin and streptomycin was suspended after it was discovered that these drugs lower complement levels and therefore could allow infectious pathogens to enter the bloodstream, increasing the likelihood of disease spread.

Clinical evidence shows that improperly functioning complement can lead to a variety of immune system disorders, especially arthritis, cataracts, and some cardiovascular diseases. Complement dysfunction is also associated with certain pathological conditions (eg, age-related macular degeneration (AMD), rheumatoid arthritis). Complement hyperactivation-induced aggregation of activated immune cells may contribute to several aspects of the inflammatory process, particularly increased proliferation in immune tissues.

One of the new areas of complement research is the use of these molecules for the treatment of inflammatory processes. Research is currently being conducted on the use of complement to kill tumors. One of the first attempts at such treatment was made using cryoablation, which destroys tumors by lowering the patient's body temperature to zero without harming healthy tissue. However, most tumor tissues are not killed by this method, as they have increased resistance to temperature changes.