Depending on the functions of lymphocytes, specific immunity is usually divided into humoral and cellular. B lymphocytes in in this case are responsible for humoral and T-lymphocytes for cellular immunity. Humoral immunity is so named because its immunocytes (B cells) produce antibodies that can be released from the cell surface. Moving along the blood or lymphatic channel - humor, antibodies attack foreign bodies at any distance from the lymphocyte. Cellular immunity is called because T-lymphocytes (mainly T-killers) produce receptors that are rigidly fixed on the cell membrane, and serve as an effective weapon for T-killers to defeat foreign cells upon direct contact with them.

At the periphery, mature T and B cells are located in the same lymphoid organs - partly isolated, partly in a mixture. But as for T-lymphocytes, their stay in organs is short-lived, because they are constantly on the move. Their lifespan (months and years) helps them do this. T-lymphocytes repeatedly leave the lymphoid organs, entering first the lymph, then the blood, and from the blood they return to the organs. Without this ability of lymphocytes, their timely development, interaction and effective participation in the immune response during the invasion of foreign molecules and cells would be impossible.

The full development of a humoral immune response requires not two, but at least three types of cells. The function of each cell type in antibody production is strictly predetermined. Macrophages and other phagocytic cells ingest, process and express the antigen in an immunogenic form accessible to T and B lymphocytes. T helper cells, after recognizing the antigen, begin to produce cytokines that provide assistance to B cells. These latter cells, having received a specific stimulus from the antigen and a nonspecific one from T cells, begin to produce antibodies. The humoral immune response is provided by antibodies, or immunoglobins. In humans, there are 5 main classes of immunoglobins: IgA, IgG, IgM, IgE, IgD. All of them have both general and specific determinants.

When forming a cellular type of immune response, cooperation between different types of cells is also necessary. Cellular immunity depends on the action of humoral factors secreted by cytotoxic lymphocytes (T-killer cells). These compounds are called perforins and cytolysins.

It has been established that each T-effector is capable of lysing several foreign target cells. This process is carried out in three stages: 1) recognition and contact with target cells; 2) lethal blow; 3) lysis of the target cell. The last stage does not require the presence of a T-effector, as it is carried out under the influence of perforins and cytolysins. During the lethal strike stage, perforins and cytolysins act on the membrane of the target cell and form pores in it through which water penetrates, tearing the cells.

Chapter VI. Immune regulatory system

The intensity of the immune response is largely determined by the state of the nervous and endocrine systems. It has been established that irritation of various subcortical structures (thalamus, hypothalamus, gray tubercle) can be accompanied by both an increase and inhibition of the immune response to the introduction of antigens. It has been shown that stimulation of the sympathetic part of the autonomic (vegetative) nervous system, as well as the administration of adrenaline, increases phagocytosis and the intensity of the immune response. An increase in the tone of the parasympathetic division of the autonomic nervous system leads to opposite reactions.

Stress depresses the immune system, which is accompanied not only by increased susceptibility to various diseases, but also creates favorable conditions for the development of malignant neoplasms.

In recent years, it has been established that the pituitary and pineal glands, with the help of cytomedins, control the activity of the thymus. The anterior lobe of the pituitary gland is a regulator of predominantly cellular, and the posterior lobe of humoral immunity.

Recently, it has been suggested that there are not two regulatory systems (nervous and humoral), but three (nervous, humoral and immune). Immunocompetent cells are able to interfere with morphogenesis, as well as regulate the course of physiological functions. There is no doubt that T lymphocytes play an extremely important role in tissue regeneration. Numerous studies show that T lymphocytes and macrophages perform “helper” and “suppressor” functions in relation to erythropoiesis and leukopoiesis. Lymphokines and monokines secreted by lymphocytes, monocytes and macrophages are capable of changing the activity of the central nervous system, cardiovascular system, respiratory and digestive organs, and regulating the contractile functions of smooth and striated muscles.

Interleukins play a particularly important role in the regulation of physiological functions, as they interfere with all physiological processes occurring in the body.

The immune system is a regulator of homeostasis. This function is carried out through the production of autoantibodies that bind active enzymes, blood clotting factors and excess hormones.

Introduction

Immunity is understood as a set of biological phenomena aimed at preserving the internal environment and protecting the body from infectious and other genetically foreign agents.

There are the following types of infectious immunity:

antibacterial

antitoxic

antiviral

antifungal

antiprotozoal Infectious immunity can be sterile (there is no pathogen in the body) and non-sterile (the pathogen is in the body). Innate immunity is present from birth; it can be specific or individual. Species immunity is the immunity of one species of animal or person to microorganisms, causing disease in other species. It is genetically determined in humans as, biological species. Species immunity is always active. Individual immunity is passive (placental immunity).

Nonspecific protective factors are as follows: skin and mucous membranes

The immune system is a collection of all lymphoid organs and clusters of lymphoid cells in the body. Lymphoid organs are divided into central ones - thymus, bone marrow, bursa of Fabricius (in birds) and its analogue in animals - Peyer's patches; peripheral - spleen, lymph nodes, solitary follicles, blood and others. Main component hers are lymphocytes. There are two main classes of lymphocytes: B lymphocytes and T lymphocytes. T cells are involved in cellular immunity

, regulation of B-cell activity, delayed-type hypersensitivity. The following subpopulations of T-lymphocytes are distinguished: T-helpers (programmed to induce the proliferation and differentiation of other types of cells), suppressor T-cells, T-killers (secrete cytotoxic dimphokines). The main function of B lymphocytes is that in response to an antigen they are able to multiply and differentiate into plasma cells that produce antibodies. B - lymphocytes are divided into two subpopulations: 15 B1 and B2. B cells are long-lived B lymphocytes, derived from mature B cells as a result of stimulation by antigen with the participation of T lymphocytes.

The immune response is a chain of sequential complex cooperative processes occurring in the immune system in response to the action of an antigen in the body. There are primary and secondary immune responses, each of which consists of two phases: inductive and productive. Further, the immune response is possible in the form of one of three options: cellular, humoral and immunological tolerance. Antigens by origin: natural, artificial and synthetic; by chemical nature: proteins, carbohydrates (dextran), nucleic acids, conjugated antigens, polypeptides, lipids; by genetic relationship: autoantigen, isoantigens, alloantigen, xenoantigens. Antibodies are proteins synthesized under the influence of an antigen.

II. Immune system cells

Immunocompetent cells are cells that are part of the immune system. All of these cells originate from a single ancestral red bone marrow stem cell. All cells are divided into 2 types: granulocytes (granular) and agranulocytes (non-granular).

Granulocytes include:

neutrophils

eosinophils

basophils

To agranulocytes:

macrophages

lymphocytes (B, T) Neutrophil granulocytes or, neutrophils, segmented neutrophils- a subtype of granulocytic leukocytes, called neutrophils because when stained according to Romanovsky, they are intensely stained with both the acidic dye eosin and basic dyes, in contrast to eosinophils, stained only with eosin, and from basophils, stained only with basic dyes.

Mature neutrophils have a segmented nucleus, that is, they belong to polymorphonuclear leukocytes, or polymorphonuclear cells.

They are classical phagocytes: they have adhesiveness, motility, the ability to chemostaxis, as well as the ability to capture particles (for example, bacteria). Mature segmented neutrophils are normally the main type of leukocyte , circulating in human blood, amounting to from 47% to 72% total number

blood leukocytes. Another 1-5% are normally young, functionally immature neutrophils that have a rod-shaped solid nucleus and do not have the nuclear segmentation characteristic of mature neutrophils - the so-called band neutrophils.

Neutrophils are capable of active amoeboid movement, extravasation (emigration outside the blood vessels), and chemotaxis (predominant movement towards sites of inflammation or tissue damage). Neutrophils are capable of phagocytosis, and they are microphages, that is, they are able to absorb only relatively small foreign particles or cells. After phagocytosis of foreign particles, neutrophils usually die, releasing large amounts of biologically active substances , damaging bacteria and fungi, increasing inflammation and chemotaxis immune cells

An increase in the proportion of neutrophils in the blood is called relative neutrophilosis, or relative neutrophilic leukocytosis.

An increase in the absolute number of neutrophils in the blood is called absolute neutrophilosis. A decrease in the proportion of neutrophils in the blood is called relative neutropenia. A decrease in the absolute number of neutrophils in the blood is designated as absolute neutropenia.

Neutrophils play very important role in protecting the body from bacterial and fungal infections, and comparatively less in protecting against viral infections. Neutrophils play virtually no role in antitumor or anthelmintic defense.

Neutrophilic response (infiltration of the inflammatory focus with neutrophils, increased number of neutrophils in the blood, shift Neutrophil granulocytes leukocyte formula, to the left with an increase in the proportion of “young” forms, indicating increased production of neutrophils by the bone marrow) - the very first response to bacterial and many other infections. The neutrophilic response in acute inflammation and infections always precedes the more specific lymphocytic response. In chronic inflammation and infections, the role of neutrophils is insignificant and the lymphocytic response predominates (infiltration of the inflammation site with lymphocytes, absolute or relative lymphocytosis in the blood)., Eosinophilic granulocytes eosinophils

segmented eosinophils eosinophilic leukocytes- a subtype of granulocytic blood leukocytes.

Eosinophils are so named because, when stained according to Romanovsky, they are intensely stained with the acidic dye eosin and are not stained with basic dyes, unlike basophils (stained only with basic dyes) and neutrophils (absorb both types of dyes). Also

hallmark

Eosinophils are less numerous than neutrophils. Most eosinophils do not remain in the blood for long and, once they enter the tissues, long time

is there.

The normal level for humans is 120-350 eosinophils per microliter. Neutrophil granulocytes Basophil granulocytes, basophils, segmented basophils basophilic leukocytes

- a subtype of granulocytic leukocytes.

They contain a basophilic S-shaped nucleus, often not visible due to the overlap of the cytoplasm with histamine granules and other allergic mediators. Basophils are so named because, when stained according to Romanovsky, they intensively absorb the main dye and are not stained with acidic eosin, unlike eosinophils, which are stained only with eosin, and neutrophils, which absorb both dyes. Basophils are very large granulocytes: they are larger than both neutrophils and eosinophils. Basophil granules contain large amounts of histamine, serotonin, leukotrienes, prostaglandins and other mediators of allergy and inflammation. Basophils take an active part in the development allergic reactions immediate type (anaphylactic shock reaction). There is a misconception that basophils are the precursors of mast cells. Mast cells are very similar to basophils. Both cells are granulated and contain histamine and heparin. Both cells also release histamine when bound to immunoglobulin E. This similarity has led many to speculate that mast cells

Basophils are capable of extravasation (emigration outside the blood vessels), and they can live outside the bloodstream, becoming resident tissue mast cells (mast cells).

Basophils have the ability to chemotaxis and phagocytosis.

In addition, apparently, phagocytosis is neither the main nor natural (carried out under natural physiological conditions) activity for basophils. Their only function is instant degranulation, leading to increased blood flow and increased vascular permeability. increased influx of fluid and other granulocytes. In other words, the main function of basophils is to mobilize the remaining granulocytes to the site of inflammation. Monocyte -

a large mature mononuclear leukocyte of the agranulocyte group with a diameter of 18-20 microns with an eccentrically located polymorphic nucleus with a loose chromatin network and azurophilic granularity in the cytoplasm.

Like lymphocytes, monocytes have a non-segmented nucleus. Monocyte is the most active phagocyte in peripheral blood. The cell is oval in shape with a large bean-shaped, chromatin-rich nucleus (which allows them to be distinguished from lymphocytes, which have a round, dark nucleus) and a large amount of cytoplasm, in which there are many lysosomes.

In addition to the blood, these cells are always present in large numbers in the lymph nodes, walls of the alveoli and sinuses of the liver, spleen and bone marrow.

Monocytes are able to phagocytose microbes in an acidic environment when neutrophils are inactive. By phagocytosis of microbes, dead leukocytes, damaged tissue cells, monocytes cleanse the site of inflammation and prepare it for regeneration.

These cells form a delimiting shaft around indestructible foreign bodies.

Activated monocytes and tissue macrophages:

participate in the regulation of hematopoiesis (blood formation)

take part in the formation of the body’s specific immune response.

Monocytes, leaving the bloodstream, become macrophages, which, along with neutrophils, are the main “professional phagocytes.” Macrophages, however, are much larger and longer-lived than neutrophils. Macrophage precursor cells - monocytes, leaving the bone marrow, circulate in the blood for several days, and then migrate into tissues and grow there. At this time, the content of lysosomes and mitochondria increases in them.

Near the inflammatory focus, they can multiply by division.

Monocytes are capable of emigrating into tissues and transforming into resident tissue macrophages.

Monocytes are also capable, like other macrophages, of processing antigens and presenting antigens to T lymphocytes for recognition and learning, that is, they are the antigen-presenting cells of the immune system.

Macrophages are large cells that actively destroy bacteria. Macrophages accumulate in large quantities in areas of inflammation. Compared to neutrophils, monocytes are more active against viruses than bacteria, and are not destroyed during a reaction with a foreign antigen, therefore, pus does not form in areas of inflammation caused by viruses. Monocytes also accumulate in areas of chronic inflammation.

Monocytes secrete soluble cytokines that affect the functioning of other parts of the immune system. Cytokines secreted by monocytes are called monokines. Monocytes synthesize individual components of the complement system.- lymphocytes that develop in mammals in the thymus from precursors - prethymocytes, entering it from the red bone marrow. In the thymus, T lymphocytes differentiate to acquire T cell receptors (TCRs) and various co-receptors (surface markers). Play an important role in the acquired immune response.

They ensure recognition and destruction of cells carrying foreign antigens, enhance the effect of monocytes, NK cells, and also take part in switching immunoglobulin isotypes (at the beginning of the immune response, B cells synthesize IgM, later switch to the production of IgG, IgE, IgA).

Types of T lymphocytes:

T-cell receptors are the main surface protein complexes of T-lymphocytes responsible for recognizing processed antigens bound to molecules of the major histocompatibility complex on the surface of antigen-presenting cells. The T cell receptor is associated with another polypeptide membrane complex, CD3.

The functions of the CD3 complex include transmitting signals into the cell, as well as stabilizing the T-cell receptor on the surface of the membrane. The T-cell receptor can associate with other surface proteins, TCR coreceptors. Depending on the coreceptor and the functions performed, two main types of T cells are distinguished. T helper cells

T helper cells - T lymphocytes,

main function

γδ T lymphocytes

γδ T lymphocytes are a small population of cells with a modified T cell receptor. Unlike most other T cells, whose receptor is formed by two α and β subunits, the T cell receptor γδ lymphocytes is formed by γ and δ subunits. These subunits do not interact with peptide antigens presented by MHC complexes. It is assumed that γδ T lymphocytes are involved in the recognition of lipid antigens.

B lymphocytes(B cells, from bursa fabricii birds where they were first discovered) - functional type lymphocytes that play an important role in providing humoral immunity.

When exposed to antigen or stimulated by T cells, some B lymphocytes transform into plasma cells capable of producing antibodies.

Other activated B lymphocytes become memory B cells. In addition to producing antibodies, B cells perform many other functions: they act as antigen-presenting cells and produce cytokines and exosomes.

In human embryos and other mammals, B lymphocytes are formed in the liver and bone marrow from stem cells, and in adult mammals - only in the bone marrow. The differentiation of B lymphocytes takes place in several stages, each of which is characterized by the presence of certain protein markers and the degree of genetic rearrangement of immunoglobulin genes.

The following types of mature B lymphocytes are distinguished:

Plasma cells are the last stage of differentiation of antigen-activated B cells. Unlike other B cells, they carry few membrane antibodies and are capable of secreting soluble antibodies. They are large cells with an eccentrically located nucleus and a developed synthetic apparatus - the rough endoplasmic reticulum occupies almost the entire cytoplasm, and the Golgi apparatus is also developed. They are short-lived cells (2-3 days) and are quickly eliminated in the absence of the antigen that caused the immune response.

A characteristic feature of B cells is the presence of surface membrane-bound antibodies related to IgM classes and IgD. In combination with other surface molecules, immunoglobulins form an antigen recognition receptive complex, responsible for antigen recognition. MHC antigens are also located on the surface of B lymphocytes class II

, important for interaction with T cells, also on some B-lymphocyte clones there is a marker CD5, common with T cells. Complement component receptors C3b (Cr1, CD35) and C3d (Cr2, CD21) play a role in the activation of B cells. It should be noted that the markers CD19, CD20 and CD22 are used to identify B lymphocytes. Fc receptors are also found on the surface of B lymphocytes. Natural killers

- large granular lymphocytes that are cytotoxic against tumor cells and cells infected with viruses.

The main function of NK is the destruction of body cells that do not carry MHC1 on their surface and are thus inaccessible to the action of the main component of antiviral immunity - T-killers.

A decrease in the amount of MHC1 on the cell surface may be a consequence of cell transformation into cancer or the action of viruses such as papillomavirus and HIV.

Macrophages, neutrophils, eosinophils, basophils and natural killer cells mediate the innate immune response, which is nonspecific.

Human immunity is a state of immunity to various infectious and generally foreign organisms and substances to the human genetic code. The body's immunity is determined by the state of its immune system, which is represented by organs and cells.

Organs and cells of the immune system Let's stop here briefly, since this is purely medical information , unnecessary.

to the common man Red bone marrow, spleen and thymus (or) – thymus central authorities .
immune system Lymph nodes and lymphoid tissue in other organs (for example, tonsils, appendix) are .

peripheral organs of the immune system Remember:

tonsils and appendix are NOT unnecessary organs, but very important organs in the human body.

The main task of the human immune system is the production of various cells.

1) What types of immune system cells are there? T lymphocytes

2) . They are divided into various cells - T-killers (kill microorganisms), T-helpers (help to recognize and kill microbes) and other types. B lymphocytes

3) . Their main task is the production of antibodies. These are substances that bind to the proteins of microorganisms (antigens, that is, foreign genes), inactivate them and are removed from the human body, thereby “killing” the infection inside the person. Neutrophils . These cells are devouring foreign cell

4) , destroy it, while also collapsing. As a result, purulent discharge appears. A typical example of the work of neutrophils is an inflamed wound on the skin with purulent discharge. Macrophages

. These cells also devour microbes, but are not destroyed themselves, but destroy them in themselves, or pass them on to T-helper cells for recognition.

There are several other cells that perform highly specialized functions. But they are of interest to specialist scientists, while the types listed above are sufficient for the common man.

Types of immunity 1) And now that we have learned what the immune system is, that it consists of central and peripheral organs

• cellular immunity
• humoral immunity.

This gradation is very important for any doctor to understand. Since many medications act on either one or the other type of immunity.

Cellular is represented by cells: T-killers, T-helpers, macrophages, neutrophils, etc.

Humoral immunity is represented by antibodies and their source – B-lymphocytes.

2) The second classification of species is based on the degree of specificity:

Nonspecific (or congenital) - for example, the work of neutrophils in any inflammatory reaction with the formation of purulent discharge,

Specific (acquired) - for example, the production of antibodies to the human papillomavirus, or to the influenza virus.

3) The third classification is types of immunity associated with medical activities person:

Natural – resulting from a human illness, for example, immunity after chickenpox,

Artificial - resulting from vaccinations, that is, the introduction of a weakened microorganism into the human body, in response to this the body develops immunity.

An example of how immunity works

Now let's take a look practical example How immunity is developed to human papillomavirus type 3, which causes the appearance of juvenile warts.

The virus penetrates into microtrauma of the skin (scratches, abrasions) and gradually penetrates further into the deeper layers of the surface layer of the skin. It was not present in the human body before, so the human immune system does not yet know how to react to it. The virus integrates into the gene apparatus of skin cells, and they begin to grow incorrectly, taking on ugly forms.

This is how a wart forms on the skin. But this process does not bypass the immune system. The first step is to turn on T-helpers. They begin to recognize the virus, remove information from it, but cannot destroy it themselves, since its size is very small, and the T-killer can only kill larger objects such as microbes.

T-lymphocytes transmit information to B-lymphocytes and they begin to produce antibodies that penetrate through the blood into skin cells, bind to virus particles and thus immobilize them, and then this entire complex (antigen-antibody) is eliminated from the body.

In addition, T lymphocytes transmit information about infected cells to macrophages. They become active and begin to gradually devour the changed skin cells, destroying them. And in place of the destroyed ones, healthy skin cells gradually grow.

The entire process can take from several weeks to months or even years. Everything depends on the activity of both cellular and humoral immunity, on the activity of all its links. After all, if, for example, at some point in time, at least one link - B-lymphocytes - drops out, then the entire chain collapses and the virus multiplies unhindered, penetrating into more and more new cells, contributing to the appearance of more and more warts on the skin.

In fact, the example presented above is only a very weak and very accessible explanation of the functioning of the human immune system. There are hundreds of factors that can turn on one mechanism or another, speeding up or slowing down the immune response.

For example, immune reaction the body to penetrate the influenza virus occurs much faster. And all because it tries to invade the brain cells, which is much more dangerous for the body than the effect of the papillomavirus.

And another clear example of how the immune system works - watch the video.

Good and weak immunity

The topic of immunity began to develop in the last 50 years, when many cells and mechanisms of the entire system were discovered. But, by the way, not all of its mechanisms have yet been discovered.

For example, science does not yet know how certain autoimmune processes are triggered in the body. This is when the human immune system, for no apparent reason, begins to perceive its own cells as foreign and begins to fight them. It’s like in 1937 – the NKVD began to fight against its own citizens and killed hundreds of thousands of people.

In general, you need to know that good immunity - This is a state of complete immunity to various foreign agents. Outwardly this is manifested by the absence infectious diseases, human health. Internally, this is manifested by the full functionality of all parts of the cellular and humoral components.

Weak immunity is a state of susceptibility to infectious diseases. It manifests itself as a weak reaction of one or another link, loss of individual links, inoperability of certain cells. There can be quite a few reasons for its decline. Therefore, it must be treated by eliminating all possible reasons. But we’ll talk about this in another article.

The term "immunity" comes from the Latin word "immunitas" - liberation, getting rid of something. It entered medical practice in the 19th century, when it began to mean “freedom from illness” (French Dictionary of Litte, 1869). But long before the term appeared, doctors had a concept of immunity in the sense of a person’s immunity to disease, which was designated as “the self-healing power of the body” (Hippocrates), “vital force” (Galen) or “healing force” (Paracelsus). Doctors have long been aware of the natural immunity (resistance) inherent in humans to animal diseases (for example, chicken cholera, canine distemper). This is now called innate (natural) immunity. Since ancient times, doctors have known that a person does not get sick from some diseases twice. So, back in the 4th century BC. Thucydides, describing the plague in Athens, noted the facts when people who miraculously survived could care for the sick without the risk of getting sick again. Life experience has shown that people can develop persistent immunity to re-infection after suffering severe infections, such as typhoid, smallpox, scarlet fever. This phenomenon is called acquired immunity.

At the end of the 18th century, the Englishman Edward Jenner used cowpox to protect people from smallpox. Convinced that artificially infecting humans was a harmless way to prevent serious illness, he conducted the first successful experiment on a person.

In China and India, smallpox vaccination was practiced several centuries before its introduction in Europe. The skin of a person who had had smallpox was scratched with the sores healthy person, who usually then suffered the infection in a mild, non-fatal form, after which he recovered and remained resistant to subsequent smallpox infections.

100 years later, the fact discovered by E. Jenner formed the basis of L. Pasteur’s experiments on chicken cholera, which culminated in the formulation of the principle of preventing infectious diseases - the principle of immunization with weakened or killed pathogens (1881).

In 1890, Emil von Behring reported that after introducing not whole diphtheria bacteria into the body of an animal, but only a certain toxin isolated from them, something appears in the blood that can neutralize or destroy the toxin and prevent the disease caused by the whole bacterium. Moreover, it turned out that preparations (serum) prepared from the blood of such animals healed children already suffering from diphtheria. The substance that neutralized the toxin and appeared in the blood only in its presence was called antitoxin. Subsequently, similar substances began to be called by the general term - antibodies. And the agent that causes the formation of these antibodies began to be called an antigen. For these works, Emil von Behring was awarded the Nobel Prize in Physiology or Medicine in 1901.

Subsequently, P. Ehrlich developed on this basis the theory of humoral immunity, i.e. immunity provided by antibodies, which, moving through liquid internal environments The body, such as blood and lymph (from the Latin humor - liquid), affects foreign bodies at any distance from the lymphocyte that produces them.

Arne Tiselius ( Nobel Prize in chemistry for 1948) showed that antibodies are just ordinary proteins, but with a very large molecular weight. The chemical structure of antibodies was deciphered by Gerald Maurice Edelman (USA) and Rodney Robert Porter (Great Britain), for which they received the Nobel Prize in 1972. It was found that each antibody consists of four proteins - 2 light and 2 heavy chains. Such a structure in an electron microscope resembles a “slingshot” in appearance (Fig. 2). The portion of the antibody molecule that binds to the antigen is highly variable and is therefore called variable. This region is contained at the very tip of the antibody, so the protective molecule is sometimes compared to tweezers, with its sharp ends grasping the smallest parts of the most intricate clockwork mechanism. The active center recognizes small regions in the antigen molecule, usually consisting of 4-8 amino acids. These sections of the antigen fit into the structure of the antibody “like a key to a lock.” If antibodies cannot cope with the antigen (microbe) on their own, other components and, first of all, special “eater cells” will come to their aid.

Later, the Japanese Susumo Tonegawa, based on the achievements of Edelman and Porter, showed what no one in principle could even expect: those genes in the genome that are responsible for the synthesis of antibodies, unlike all other human genes, have the amazing ability to repeatedly change their structure in individual human cells during his life. At the same time, varying in their structure, they are redistributed so that they are potentially ready to ensure the production of several hundred million different antibody proteins, i.e. much more than the theoretical amount of foreign substances potentially acting on the human body from outside - antigens. In 1987, S. Tonegawa was awarded the Nobel Prize in Physiology or Medicine "for the discovery genetic principles generation of antibodies."

Simultaneously with the creator of the theory of humoral immunity, Ehrlich, our compatriot I.I. Mechnikov developed the theory of phagocytosis and substantiated the phagocytic theory of immunity. He proved that animals and humans have special cells - phagocytes - capable of absorbing and destroying pathogenic microorganisms and other genetically foreign material found in our body. Phagocytosis has been known to scientists since 1862 from the works of E. Haeckel, but only Mechnikov was the first to connect phagocytosis with the protective function of the immune system. In the subsequent long-term discussion between supporters of the phagocytic and humoral theories, many mechanisms of immunity were revealed. Phagocytosis, discovered by Mechnikov, was later called cellular immunity, and antibody formation, discovered by Ehrlich, was called humoral immunity. It all ended with both scientists being recognized by the world scientific community and sharing the Nobel Prize in Physiology or Medicine for 1908.

Good day, dear readers.

Today I would like to raise a very important topic, which concerns the components of immunity. Cellular and humoral do not allow development infectious diseases, and suppress growth cancer cells in the human body. Human health depends on how well the protective processes proceed. There are two types: specific and nonspecific. Below you will find characteristics of protective forces human body, and also - what is the difference between cellular and humoral immunity.

Basic concepts and definitions

Ilya Ilyich Mechnikov is the scientist who discovered phagocytosis and laid the foundation for the science of immunology. Cellular immunity does not involve humoral mechanisms - antibodies, and is carried out through lymphocytes and phagocytes. Thanks to this protection, the human body destroys tumor cells and infectious agents. Main actor cellular immunity - lymphocytes, the synthesis of which occurs in the bone marrow, after which they migrate to the thymus. It is because of their movement into the thymus that they were called T-lymphocytes. When some threat is detected in the body, these immunocompetent cells quickly leave their habitats (lymphoid organs) and rush to fight the enemy.

There are three types of T-lymphocytes, which play an important role in protecting the human body. The function of destroying antigens is played by T-killers. Helper T cells are the first to know that a foreign protein has entered the body and in response they secrete special enzymes that stimulate the formation and maturation of killer T cells and B cells. The third type of lymphocytes are T-suppressor cells, which, if necessary, suppress the immune response. With a lack of these cells, the risk increases autoimmune diseases. The humoral and cellular defense systems of the body are closely interconnected and do not function separately.

The essence of humoral immunity lies in the synthesis of specific antibodies in response to each antigen that enters the human body. It is a protein compound found in blood and other biological fluids.

Nonspecific humoral factors are:

• interferon (protection of cells from viruses);
• C-reactive protein, which triggers the complement system;
• lysozyme, which destroys the walls of a bacterial or viral cell, dissolving it.

Specific humoral components are represented by specific antibodies, interleukins and other compounds.

Immunity can be divided into innate and acquired. Congenital factors include:

• skin and mucous membranes;
• cellular factors - macrophages, neutrophils, eosinophils, dendritic cells, natural killer cells, basophils;
• humoral factors - interferons, complement system, antimicrobial peptides.

Acquired is formed during vaccination and during the transmission of infectious diseases.

Thus, the mechanisms of nonspecific and specific cellular and humoral immunity are closely related to each other, and the factors of one of them take an active part in the implementation of the other type. For example, leukocytes are involved in both humoral and cellular defense. Violation of one of the links will lead to a systemic failure of the entire protection system.

Assessment of species and their general characteristics

When a microbe enters the human body, it triggers complex immune processes, using specific and nonspecific mechanisms. In order for a disease to develop, the microorganism must pass through a number of barriers - the skin and mucous membranes, subepithelial tissue, regional lymph nodes and the bloodstream. If it does not die when it enters the blood, it will spread throughout the body and enter the internal organs, which will lead to generalization of the infectious process.

The differences between cellular and humoral immunity are insignificant, since they occur simultaneously. It is believed that the cellular one protects the body from bacteria and viruses, and the humoral one protects the body from fungal flora.

What are there immune response mechanisms you can see in the table.

The links of the physiological chains of immunity are shown in the diagram.

Methods for assessing the state of the immune system

To assess a person’s immune status, you will have to undergo a series of tests, and you may even have to do a biopsy and send the result for histology.

Let us briefly describe all the methods:

• general clinical trial;
• state of natural protection;
• humoral (determination of immunoglobulin content);
• cellular (determination of T-lymphocytes);
• additional tests include determining C-reactive protein, complement components, rheumatoid factors.

That's all I wanted to tell you about the protection of the human body and its two main components - humoral and cellular immunity. A Comparative characteristics showed that the differences between them are very conditional.