What is immunity?

This article will talk about what is immunity, types of immunity and its functions. Immunity is called immunity of the body to infections and resistance to the effects of foreign substances (with antigenic properties). Immune reactions also appear on the body's own cells, which are modified in antigenic terms. The biological function of the immune system is to ensure its genetic integrity throughout the life of the organism. Here is a summary of what is immunity. Next, we will focus on the types of immunity.

Congenital and Acquired Immunity

Immunity has the following types: congenital and acquired. So what is innate immunity? Congenital immunity is caused by anatomical, physiological, molecular cellular features that are hereditarily fixed. Examples: the immunity of people to the plague of dogs, the immunity of some people to tuberculosis. Congenital immunity is the ability inherent in the body to neutralize a potentially dangerous biomaterial (microorganisms, toxins, tumor cells, transplant, cells infected with a virus).This ability exists initially, that is, before the first ingestion of a similar biomaterial into the body.

Inborn immunity is sometimes called non-specific and constitutional. However, at the present time, the term “constitutional immunity” is considered obsolete. This phenomenon is not being studied in immunology. Inborn immunity should not be identified with constitutional, as in the case of constitutional immunity there is usually no immune response: the pathogen simply cannot enter the body or cause harm if it can penetrate.

And now that such specific immunity. Acquired (specific) immunity is manifested in the body's ability to neutralize alien, potentially dangerous microorganisms that have previously entered the body. This is the result of the work of lymphocytes, which are located throughout the body.

Acquired immunity can be:

  • active (appears after administration of the vaccine or as a result of the disease);
  • passive (develops when the finished antibodies are transferred to the newborn by the intrauterine method or with mother's colostrum, as well as when the finished antibodies are introduced into the body in the form of serum).

Natural and artificial immunity

Immunity happens:

  • natural (innate immunity, acquired after an illness, active immunity, passive in the case of the transfer of antibodies from the mother to the child);
  • artificial (acquired active after vaccine administration, acquired passive - administration of serum).

Cellular immunity

And now that is cellular immunity. This is a type of immune response in which antibodies and the complement system are not involved. In cellular immunity, macrophages are activated, antigen-specific cytotoxic T-lymphocytes, natural killer cells, and cytokines are released in response to the antigen.

Historically, the immune system consists of two parts:

  • systems of humoral immunity (while the protective functions are performed by molecules that are in the blood plasma, and not cellular elements);
  • systems of cellular immunity (cells of the immune system perform a protective function).

Cellular immunity is mainly directed against microorganisms that survive in phagocytes or infect other cells. A particularly effective system of cellular immunity against cells that are infected with viruses.Also, cellular immunity is involved in protection from protozoa, intracellular bacteria, fungi, tumor cells.

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