Good afternoon, dear readers!
Last time I told you about a very important group of blood cells - which are the real front line fighters immune defense. But they are not the only participants in operations to capture and destroy “enemy agents” in our body. They have assistants. And today I want to continue my story and study functions leukocytes - agranulocytes. This group also includes lymphocytes, the cytoplasm of which lacks granularity.
Monocyte is the largest representative of leukocytes. The diameter of its cell is 10 – 15 microns, the cytoplasm is filled with a large bean-shaped nucleus. There are few of them in the blood, only 2–6%. But in the bone marrow they are formed in large quantities and mature in the same microcolonies as neutrophils. But when they enter the blood, their paths diverge. Neutrophils travel through blood vessels and are always in readiness No. 1. And monocytes quickly spread throughout the organs and there turn into macrophages. Half of them go to the liver, and the rest are distributed to the spleen, intestines, lungs, etc.

Macrophages– these are sedentary, finally matured. Like neutrophils, they are capable of phagocytosis, but, in addition, they have their own sphere of influence and other specific tasks. Under a microscope, a macrophage is a very visible cell with impressive dimensions up to 40 - 50 microns in diameter. This is a real mobile factory for the synthesis of special proteins for its own needs and for neighboring cells. It turns out that a macrophage can synthesize and secrete up to 80 per day! various chemical compounds. You ask: what active substances secreted by macrophages? It depends on where macrophages live and what functions they perform.

Functions of leukocytes:

Let's start with bone marrow. There are two types of macrophages involved in the process of bone tissue renewal - osteoclasts and osteoblasts. Osteoclasts constantly circulate through bone tissue, finding old cells and destroying them, leaving behind free space for future bone marrow, and osteoblasts form new tissue. Macrophages perform this work by synthesizing and secreting special stimulating proteins, enzymes and hormones. For example, to destroy bone they synthesize collagenase and phosphatase, and to grow red blood cells - erythropoietin.
There are also “nurse” cells and “nurse” cells that ensure rapid reproduction and normal maturation of blood cells in the bone marrow. Hematopoiesis in the bones occurs in islands - in the middle of such a colony there is a macrophage, and red cells are crowded around of different ages. Performing the function of a nursing mother, the macrophage supplies growing cells with nutrition - amino acids, carbohydrates, fatty acids.

They play a special role in the liver. There they are called Kupffer cells. Actively working in the liver, macrophages absorb various harmful substances and particles coming from the intestines. Together with liver cells, they participate in processing fatty acids, cholesterol and lipids. Thus, they unexpectedly turn out to be involved in the formation of cholesterol plaques on the walls of blood vessels and the occurrence of atherosclerosis.

It is not yet entirely clear where the atherosclerotic process begins. Perhaps an erroneous reaction to “their” lipoproteins in the blood is triggered here, and macrophages, like vigilant immune cells, begin to capture them. It turns out that the gluttony of macrophages has both positive and negative aspects. Capturing and destroying microbes is, of course, a good thing. But excessive absorption of fatty substances by macrophages is bad and probably leads to a pathology dangerous to human health and life.

But it is difficult for macrophages to separate what is good and what is bad, so our task is to alleviate the fate of macrophages and take care of our own health and the health of the liver: monitor nutrition, reduce the consumption of foods containing large number fats and cholesterol and remove waste and toxins twice a year.

Now let's talk about macrophages, working in the lungs.

The inhaled air and blood in the pulmonary vessels are separated by a thin border. Do you understand how important it is to ensure sterility under these conditions? airways! That's right, here this function is also performed by macrophages wandering around connective tissue lungs.
They are always filled with the remains of dead lung cells and microbes inhaled from the surrounding air. Lung macrophages multiply immediately in the area of ​​their activity, and their number increases sharply with chronic diseases respiratory tract.

Attention smokers! Dust particles and tarry substances from tobacco smoke greatly irritate the upper respiratory tract paths, damage the mucous cells of the bronchi and alveoli. Pulmonary macrophages, of course, capture and neutralize these harmful chemical products. In smokers, the activity, number and even size of macrophages sharply increases. But after 15–20 years, the limit of their reliability is exhausted. The delicate cellular barriers separating air and blood are broken, the infection breaks into the depths of the lung tissue and inflammation begins. Macrophages are no longer able to fully work as microbial filters and give way to granulocytes. Thus, long-term smoking leads to chronic bronchitis and a decrease in the respiratory surface of the lungs. Overly active macrophages corrode the elastic fibers of the lung tissue, which leads to difficulty breathing and hypoxia.

The saddest thing is that, working for wear, macrophages stop performing very important functions– this is the ability to fight malignant cells. That's why chronic hepatitis is fraught with the development of liver tumors, and chronic pneumonia is fraught with lung cancer.

Macrophages spleen.

In the spleen, macrophages perform the function of “killers”, destroying aging red blood cells. On the membranes of red blood cells, treacherous proteins are exposed, which are a signal for elimination. By the way, the destruction of old red blood cells occurs both in the liver and in the bone marrow itself - wherever there are macrophages. In the spleen this process is most obvious.

Thus, macrophages are great workers and the most important orderlies of our body, performing several key roles at once:

1. participation in phagocytosis,
2. preservation and processing of important nutrients for the body's needs,
3. release of several dozen proteins and other biologically active substances that regulate the growth of blood cells and other tissues.

Well, we know functions of leukocytes - monocytes and macrophages. And again there was no time left for lymphocytes. We will talk about them, the smallest defenders of our body, next time.
In the meantime, let's get healthy and strengthen our immune system by listening to the healing music of Mozart - Symphony of the Heart:

I wish you good health and prosperity!

№ 1 immunity. Types of immunity.

Immunity is a way of protecting the body from genetically foreign substances - antigens, aimed at maintaining and preserving homeostasis, the structural and functional integrity of the body.

1. Innate immunity is a genetically fixed, inherited immunity of a given species and its individuals to any antigen, developed in the process of phylogenesis, determined by the biological characteristics of the organism itself, the properties of this antigen, as well as the characteristics of their interaction. (example: plague cattle)

innate immunity can be absolute and relative. For example, frogs that are not sensitive to tetanus toxin may respond to its administration by raising their body temperature.

Species immunity can be explained from different positions, primarily by the absence of a particular type of receptor apparatus that provides the first stage of interaction of a given antigen with cells or target molecules that determine the initiation of a pathological process or activation immune system. The possibility of rapid destruction of the antigen, for example, by body enzymes, or the absence of conditions for the engraftment and reproduction of microbes (bacteria, viruses) in the body, cannot be excluded. Ultimately this is due genetic characteristics species, in particular the absence of immune response genes to a given antigen.

2. Acquired immunity is immunity to an antigen of a sensitive human organism, animals, etc., acquired in the process of ontogenesis as a result of a natural encounter with this antigen of the body, for example, during vaccination.

An example of natural acquired immunity a person may have immunity to infection that occurs after an illness, the so-called post-infectious

Acquired immunity can be active or passive. Active immunity is due to an active reaction, active involvement of the immune system in the process when it encounters a given antigen (for example, post-vaccination, post-infectious immunity), and passive immunity is formed by introducing ready-made immunoreagents into the body that can provide protection against the antigen. Such immunoreagents include antibodies, i.e. specific immunoglobulins and immune sera, as well as immune lymphocytes. Immunoglobulins are widely used for passive immunization.

distinguish between cellular, humoral, cellular-humoral and humoral-cellular immunity.

Example cellular immunity can serve as antitumor, as well as transplantation immunity, when the leading role in immunity is played by cytotoxic killer T-lymphocytes; immunity during infections (tetanus, botulism, diphtheria) is mainly due to antibodies; in tuberculosis, the leading role is played by immunocompetent cells (lymphocytes, phagocytes) with the participation of specific antibodies; in some viral infections (smallpox, measles, etc.), specific antibodies, as well as cells of the immune system, play a role in protection.

In infectious and non-infectious pathology and immunology, to clarify the nature of immunity depending on the nature and properties of the antigen, the following terminology is also used: antitoxic, antiviral, antifungal, antibacterial, antiprotozoal, transplantation, antitumor and other types of immunity.

Finally, the immune state, i.e. active immunity, can be maintained or maintained either in the absence or only in the presence of an antigen in the body. In the first case, the antigen plays the role of a triggering factor, and immunity is called sterile. In the second case, immunity is interpreted as non-sterile. An example of sterile immunity is post-vaccination immunity with the introduction of killed vaccines, and non-sterile immunity is immunity in tuberculosis, which persists only in the presence of Mycobacterium tuberculosis in the body.

Immunity (antigen resistance) can be systemic, i.e. generalized, and local, in which more pronounced resistance is observed individual organs and tissues, such as the mucous membranes of the upper respiratory tract (which is why it is sometimes called mucosal).

№2 Antigens..

Antigens are foreign substances or structures that are capable of causing an immune response.

Antigen characteristics:

Immunogenicity- This is the property of an antigen to cause an immune response.

Antigen specificity- this is the ability of an antigen to selectively react with antibodies or sensitized lymphocytes that appear as a result of immunization. Certain parts of its molecule, called determinants (or epitopes), are responsible for the specificity of an antigen. The specificity of an antigen is determined by a set of determinants.

CLASSIFICATION OF ANTIGENS:

The main types of bacterial antigens are:

Somatic or O-antigens (in gram-negative bacteria, specificity is determined by deoxysugars of LPS polysaccharides);

Flagellar or H-antigens (protein);

Surface or capsular K antigens.

№3 Antibodies (immunoglobulins.)

Antibodies are serum proteins produced in response to an antigen. They belong to serum globulins and are therefore called immunoglobulins (Ig). Through them, the humoral type of immune response is realized. Antibodies have 2 properties: specificity, i.e. the ability to interact with an antigen similar to the one that induced (caused) their formation; heterogeneity in physical and chemical structure, specificity, genetic determination of formation (by origin). All immunoglobulins are immune, that is, they are formed as a result of immunization and contact with antigens. Nevertheless, based on their origin, they are divided into: normal (anamnestic) antibodies, which are found in any body as a result of household immunization; infectious antibodies, which accumulate in the body during an infectious disease; post-infectious antibodies, which are found in the body after an infectious disease; post-vaccination antibodies that arise after artificial immunization.

№4 nonspecific protective factors and their characteristics

1) humoral factors - complement system. Complement is a complex of 26 proteins in the blood serum. Each protein is designated as a fraction in Latin letters: C4, C2, C3, etc. Under normal conditions, the complement system is in an inactive state. When antigens enter, it is activated; the stimulating factor is the antigen-antibody complex. Any infectious inflammation begins with the activation of complement. The complement protein complex is integrated into the cell membrane of the microbe, which leads to cell lysis. Complement is also involved in anaphylaxis and phagocytosis, as it has chemotactic activity. Thus, complement is a component of many immunolytic reactions aimed at freeing the body from microbes and other foreign agents;

2) cellular protection factors.

Phagocytes. Phagocytosis (from the Greek phagos - devour, cytos - cell) was first discovered by I. I. Mechnikov, for this discovery in 1908 he received Nobel Prize. The mechanism of phagocytosis consists of the absorption, digestion, and inactivation of substances foreign to the body by special phagocyte cells. Mechnikov classified macrophages and microphages as phagocytes. Currently, all phagocytes are united into a single phagocytic system. It includes: promonocytes - produced by bone marrow; macrophages - scattered throughout the body: in the liver they are called “Kupffer cells”, in the lungs - “alveolar macrophages”, in bone tissue - “osteoblasts”, etc. The functions of phagocyte cells are very diverse: they remove dying cells from the body, absorb and inactivate microbes, viruses, fungi; synthesize biologically active substances (lysozyme, complement, interferon); participate in the regulation of the immune system.

The process of phagocytosis, i.e. the absorption of a foreign substance by phagocyte cells, occurs in 4 stages:

1) activation of the phagocyte and its approach to the object (chemotaxis);

2) adhesion stage - adherence of the phagocyte to the object;

3) absorption of an object with the formation of a phagosome;

4) formation of a phagolysosome and digestion of the object using enzymes.

№5 Organs, tissues and cells of the immune system

There are central and peripheral organs of the immune system, in which cells of the immune system develop, mature and differentiate.

The central organs of the immune system are the bone marrow and thymus. In them, from hematopoietic stem cells, lymphocytes differentiate into mature non-immune lymphocytes, the so-called naive lymphocytes (from the English naive), or virgin (from the English virgine).

Hematopoietic bone marrow is the birthplace of all cells of the immune system and the maturation of B lymphocytes (B lymphopoiesis).

The thymus (thymus gland) is responsible for the development of T-lymphocytes: T-lymphopoiesis (rearrangement, i.e. rearrangement of TcR genes, receptor expression, etc.). In the thymus, T-lymphocytes (CD4 and CD8) are selected and cells that are highly avid to self-antigens are destroyed. Thymic hormones complete the functional maturation of T-lymphocytes and increase their secretion of cytokines. The ancestor of all cells of the immune system is the hematopoietic stem cell. From lymphoid stem cells, precursors of T and B cells are formed, which serve as a source of T and B lymphocyte populations. T lymphocytes develop in the thymus under the influence of its humoral mediators (thymosin, thymopoectin, timorin, etc.). Subsequently, thymus-dependent lymphocytes settle in peripheral lymphoid organs and transform. T 1 - cells are localized in the periarterial zones of the spleen, react weakly to the action of radiant energy and are precursors of effectors of cellular immunity, T 2 - cells accumulate in the pericortical zones of the lymph nodes, are highly radiosensitive and are distinguished by antigen reactivity.

Peripheral lymphoid organs and tissues (lymph nodes, lymphoid structures of the pharyngeal ring, lymphatic ducts and spleen) is the territory of interaction of mature non-immune lymphocytes with antigen-presenting cells (APCs) and subsequent antigen-dependent differentiation (immunogenesis) of lymphocytes. This group includes: skin-associated lymphoid tissue); lymphoid tissue associated with the mucous membranes of the gastrointestinal, respiratory and genitourinary tracts (solitary follicles, tonsils, Peyer's patches, etc.). Peyer's patches (group lymphatic follicles) are lymphoid formations of the wall of the small intestine. Antigens penetrate from the intestinal lumen into Peyer's patches through epithelial cells (M cells).

№6 T cells of the immune system, their characteristics

T lymphocytes participate in cellular immunity reactions: allergic reactions delayed type, transplant rejection reactions and others, provide antitumor immunity. The T-lymphocyte population is divided into two subpopulations: CD4 lymphocytes - T-helpers and CD8 lymphocytes - cytotoxic T-lymphocytes and T-suppressors. In addition, there are 2 types of T helper cells: Th1 and Th2

T lymphocytes. Characteristics of T-lymphocytes. Types of molecules on the surface of T lymphocytes. The decisive event in the development of T lymphocytes, the formation of the antigen recognition T cell receptor, occurs only in the thymus. To ensure the possibility of recognizing any antigen, millions of antigen recognition receptors with different specificities are needed. The formation of a huge variety of antigen recognition receptors is possible due to gene rearrangement during the proliferation and differentiation of progenitor cells. As T-lymphocytes mature, antigen-recognition receptors and other molecules appear on their surface, mediating their interaction with antigen-presenting cells. Thus, CD4 or CD8 molecules participate in the recognition of self-molecules of the major histocompatibility complex, along with the T-cell receptor. Intercellular contacts are provided by sets of surface adhesion molecules, each of which corresponds to a ligand molecule on the surface of another cell. As a rule, the interaction of a T lymphocyte with an antigen-presenting cell is not limited to recognition of the antigen complex by the T-cell receptor, but is accompanied by the binding of other pairwise complementary surface “costimulatory” molecules. Table 8.2. Types of molecules on the surface of T-lymphocytes Molecules Functions Antigen recognition receptor: T-cell receptor Recognition and binding of the complex: antigenic peptide + own molecule of the major histocompatibility complex Coreceptors: CD4, CD8 Participate in the binding of the molecule of the major histocompatibility complex Adhesion molecules Adhesion of lymphocytes to endothelial cells, to antigen-presenting cells, to elements of the extracellular matrix Costimulatory molecules Participate in the activation of T-lymphocytes after interaction with an antigen Immunoglobulin receptors Bind immune complexes Cytokine receptors Bind cytokines A combination of surface molecules of lymphocytes, which are usually designated by serial numbers of “clusters of differentiation” (CD), is referred to as the “cell surface phenotype,” and individual surface molecules are called “markers” because they serve as markers of specific subpopulations and stages of T lymphocyte differentiation. For example, at the later stages of differentiation, some T lymphocytes lose the CD8 molecule and retain only CD4, while others lose CD4 and retain CD8. Therefore, among mature T-lymphocytes, CD4+ (T-helper cells) and CD8+ (cytotoxic T-lymphocytes) are distinguished. Among T-lymphocytes circulating in the blood, there are approximately twice as many cells with the CD4 marker as there are cells with the CD8 marker. Mature T lymphocytes carry receptors for various cytokines and receptors for immunoglobulins on their surface (Table 8.2). When a T cell receptor recognizes an antigen, T lymphocytes receive activation, proliferation, and differentiation signals toward effector cells, i.e., cells that can directly participate in protective or damaging effects. To achieve this, the number of adhesion and costimulatory molecules, as well as receptors for cytokines, sharply increases on their surface. Activated T lymphocytes begin to produce and secrete cytokines that activate macrophages, other T lymphocytes, and B lymphocytes. After completion of the infection, associated with enhanced production, differentiation and activation of T-effectors of the corresponding clone, within a few days 90% of the effector cells die because they do not receive additional activation signals. Long-lived memory cells remain in the body, carrying receptors corresponding in specificity and capable of responding with proliferation and activation to a repeated encounter with the same antigen.

№7 B cells of the immune system, their characteristics

B lymphocytes constitute about 15-18% of all lymphocytes found in peripheral blood. After recognizing a specific antigen, these cells multiply and differentiate, transforming into plasma cells. Plasma cells produce large amounts of antibodies (immunoglobulins Ig), which are their own receptors for B lymphocytes in dissolved form. The main component of immunoglobulins Ig (monomer) consists of 2 heavy and 2 light chains. Fundamental difference between immunoglobulins lies in the structure of their heavy chains, which are represented by 5 types (γ, α, µ, δ, ε).

8. Macrophages

Macrophages are large cells formed from monocytes, capable of phagocytosis. In addition to direct phagocytosis,

macrophages take part in the complex processes of the immune response, stimulating lymphocytes and other immune cells.

In fact, a monocyte becomes a macrophage when it leaves the vascular bed and penetrates the tissue.

Depending on the type of tissue, there are the following types macrophages.

Histiocytes are connective tissue macrophages; component of the reticuloendothelial system.

Kupffer cells - otherwise endothelial stellate cells of the liver.

Alveolar macrophages - otherwise, dust cells; located in the alveoli.

Epithelioid cells are the components of granulomas.

Osteoclasts are multinucleated cells involved in bone resorption.

Microglia are cells of the central nervous system that destroy neurons and absorb infectious agents.

Macrophages of the spleen

Macrophage functions include phagocytosis, antigen processing, and interaction with cytokines.

Non-immune phagocytosis: macrophages are able to phagocytose foreign particles, microorganisms and debris

damaged cells directly, without causing an immune response. “Processing” of antigens:

macrophages “process” antigens and present them to B and T lymphocytes in the required form.

Interaction with cytokines: macrophages interact with cytokines produced by T lymphocytes

to protect the body against certain damaging agents.

9. Cell cooperation in the immune response.

Patrol macrophages, having discovered foreign proteins (cells) in the blood, present them to T-helper cells

(happens processing Ag macrophages). T helper cells transmit antigen information to B lymphocytes,

which begin to blast transform and proliferate, releasing the necessary immunoglobulin.

A minority of T helper cells (inducers) stimulate macrophages and macrophages begin to produce

interleukin I– activator of the main part of T-helpers. Those, getting excited, in turn announce

general mobilization, beginning to vigorously highlight interleukin II (lymphokine), which accelerates proliferation and

T-helpers and T-killers. The latter have a special receptor specifically for those protein determinants

which were presented by patrolling macrophages.

Killer T cells rush to target cells and destroy them. At the same time, interleukin II

promotes the growth and maturation of B lymphocytes, which turn into plasma cells.

The same interleukin II will breathe life into T-suppressors, which close the overall reaction of the immune response,

stopping the synthesis of lymphokines. The proliferation of immune cells stops, but memory lymphocytes remain.

10.Allergies

Specifically increased sensitivity organism of a pathogenic nature to substances with antigenic properties.

Classification:

1.immediate type hypersensitivity reactions: develop within a few minutes. Antibodies are involved. Therapy with antihistamines. Diseases - atopic bronchial asthma, urticaria, serum sickness

2. delayed-type hypersensitivity reactions: after 4-6 hours, symptoms increase within 1-2 days. There are no antibodies in the serum, but there are lymphocytes that can recognize the antigen with the help of their receptors. Diseases - bacterial allergy, contact dermatitis, transplant rejection reactions.

4 types of reactions for jel and cubes:

Type 1 anaphylactic reactions: they are caused by the interaction of antigens entering the body with antibodies ( IgE), deposited on the surface of mast cells and basophils. These target cells are activated and biologically active substances (histamine, serotonin) are released. This is how anaphylaxis and atopic bronchial asthma develop.

Type 2 cytotoxic: Antibodies circulating in the blood interact with antigens fixed on cell membranes. As a result, the cells are damaged and cytolysis occurs. Autoimmune hemolytic anemia, hemolytic disease of the newborn.

Type 3 reaction of immune complexes: circulating antibodies interact with circulating antigens. The resulting complexes settle on the walls of blood capillaries, damaging the blood vessels. Serum sickness of daily injections

Type 4 cell-mediated immune reactions: they do not depend on the presence of antibodies, but are associated with the reactions of thymus-dependent lymphocytes. T-lymphocytes damage foreign cells. Transplantation, bacterial allergy.

Type 5 anti-receptor: antibodies interact with hormone receptors on the cell membrane. This leads to cell activation. Graves' disease (increased thyroid hormones)

11.Immunodeficiencies

Immunodeficiencies are a certain degree of deficiency or loss of normal function the body's immune system, as a result of genetic or other types of damage. Genetic analysis identifies a spectrum of chromosomal abnormalities in immunodeficiencies: from chromosome deletions and point mutations to changes in transcription and translation processes.

Immunodeficiency conditions

accompanied by many pathological processes. There is no single generally accepted classification of immunodeficiencies. Many authors divide immunodeficiencies into “primary” and “secondary”. Congenital forms of immunodeficiency are based on a genetic defect. Abnormalities in chromosomes, primarily the 14th, 18th and 20th, are of primary importance.

Depending on which effector links led to the development of immunodeficiency, one should distinguish between deficits of specific and nonspecific links of the body's resistance.

Congenital immunodeficiency conditions

A. Immunodeficiencies of a specific link:

T-cell deficiencies:

variable immunodeficiencies.

Selective immunodeficiency for the Ir gene.

B-cell deficiencies:

Combined immunodeficiencies:

Selective Deficiencies:

B. Nonspecific immunodeficiencies

Lysozyme deficiency.

Complement system deficiencies:

Deficiencies in phagocytosis.

Secondary immunodeficiencies

Diseases of the immune system.

Generalized bone marrow disorders.

Infectious diseases.

Metabolic disorders and intoxication.

Exogenous influences.

Immunodeficiencies during aging.

HIV infection. Human immunodeficiency virus (HIV) causes infectious disease mediated by primary damage to the immune system virus, with bright

expressed secondary immunodeficiency, which causes the development of diseases caused by opportunistic infections.

HIV has an affinity for lymphoid tissue, specifically T-helper cells. The HIV virus in patients is found in the blood, saliva, and seminal fluid. Therefore, infection is possible through transfusion of such blood, sexually, or vertically.

It should be noted that disorders of the cellular and humoral components of the immune response in AIDS are characterized by:

a) decrease total number T-lymphocytes, due to T-helpers

b) decrease in the function of T-lymphocytes,

c) increasing the functional activity of B-lymphocytes,

d) an increase in the number of immune complexes,

k) decrease in the cytotoxic activity of natural killer cells,

f) decreased chemotaxis, cytotoxicity of macrophages, decreased production of IL-1.

Immunological disorders are accompanied by an increase in alpha interferon, the appearance of antilymphocyte antibodies, suppressive factors, a decrease in thymosin in the blood serum, and an increase in the level of β2-microglobulins.

The causative agent of the disease is human T-lymphocyte virus

Such microorganisms usually live on the skin and mucous membranes, called resident microflora. The disease has a phase character. The period of pronounced clinical manifestations is called acquired immunodeficiency syndrome (AIDS).

am, supporting the implementation of the immune response (Fig. 6).

The main property of a macrophage (Fig. 4) is the ability for phagocytosis - selective endocytosis and further destruction of objects containing pathogen-associated molecular templates or attached opsonins (Fig. 5, 6).

Macrophage receptors

To detect such objects, macrophages contain on their surface template recognition receptors (in particular, the mannose-binding receptor and the receptor for bacterial lipopolysaccharides), as well as receptors for opsonins (for example, for C3b and Fc fragments of antibodies).

Macrophages on their surface express receptors that provide adhesion processes (for example, CDllc and CDllb), perception of regulatory influences and participation in intercellular interaction. Thus, there are receptors for various cytokines, hormones, and biologically active substances.

Bacteriolysis

Antigen presentation

While the captured object is being destroyed, the number of pattern recognition receptors and opsonin receptors on the macrophage membrane significantly increases, which allows phagocytosis to continue, and the expression of class II major histocompatibility complex molecules involved in presentation processes also increases (recommendations) antigen to immunocompetent cells. In parallel, the macrophage synthesizes preimmune cytokines (primarily IL-1β, IL-6 and tumor necrosis factor α), which attract other phagocytes to work and activate immunocompetent cells, preparing them for the upcoming antigen recognition. The remains of the pathogen are removed from the macrophage by exocytosis, and immunogenic peptides in complex with HLA II enter the cell surface to activate T helper cells, i.e. maintaining the immune response.

Well known important role macrophages in aseptic inflammation, which develops in foci of non-infectious necrosis (in particular, ischemic). Thanks to the expression of receptors for “garbage” (scavenger receptor), these cells effectively phagocytose and neutralize elements of tissue detritus.

Also, it is macrophages that capture and process foreign particles (for example, dust, metal particles), various reasons entered the body. The difficulty of phagocytosis of such objects is that they are absolutely devoid of molecular templates and do not fix opsonins. To get out of this difficult situation, the macrophage begins to synthesize components of the intercellular matrix (fibronectin, proteoglycans, etc.), which envelop the particle, i.e. artificially creates such surface structures that are easily recognized. Material from the site

It has been established that due to the activity of macrophages, a restructuring of metabolism occurs during inflammation. Thus, TNF-α activates lipoprotein lipase, which mobilizes lipids from the depot, which, when long term inflammation leads to weight loss. Due to the synthesis of pre-immune cytokines, macrophages are able to inhibit the synthesis of a number of products in the liver (for example, TNF-α inhibits the synthesis of albumin by hepatocytes) and increase the formation of acute-phase proteins (primarily due to IL-6), related mainly to globulin fraction. Such repurposing of hepatocytes along with an increase in synthesis

Macrophages Monocytes (macrophages) - white type blood cells involved in the fight against infections. Monocytes, along with neutrophils, are the two main types of blood cells that engulf and destroy various microorganisms. When monocytes leave the blood and enter tissues, they turn into macrophages. Macrophages are close in their functions to monocytes and can fight infections in tissues, as well as perform some other functions, for example, utilize dead cells (scavengers)

Source: "Medical Dictionary"

Connective tissue cells with active mobility and a pronounced ability for phagocytosis - absorption and destruction of foreign cells.

Source: "Medical Popular Encyclopedia"

Medical terms. 2000 .

See what “Macrophages” are in other dictionaries:

- ... Wikipedia

MACROPHAGES- (from the Greek makros: large and phago eat), vulture. megalophages, macrophagocytes, large phagocytes. The term M. was proposed by Mechnikov, who divided all cells capable of phagocytosis into small phagocytes, microphages (see), and large phagocytes, macrophages. Under… … Big medical encyclopedia

- (from macro... and...phage) (polyblasts) cells of mesenchymal origin in animals and humans, capable of actively capturing and digesting bacteria, cell debris and other particles foreign or toxic to the body (see Phagocytosis). To macrophages... Big Encyclopedic Dictionary

- (from macro... and...phage), cells of mesenchymal origin in an animal body, capable of actively capturing and digesting bacteria, the remains of dead cells and other particles foreign and toxic to the body. The term "M." introduced by I.I.... ... Biological encyclopedic dictionary

The main cell type of the mononuclear phagocyte system. These are large (10-24 microns) long-lived cells with a well-developed lysosomal and membrane apparatus. On their surface there are receptors for the Fc fragment of IgGl and IgG3, C3b fragment C, B receptors ... Dictionary of microbiology

MACROPHAGES- [from macro... and phage (and)], organisms that devour large prey. Wed. Microphages. Ecological encyclopedic dictionary. Chisinau: Main editorial office of the Moldavian Soviet Encyclopedia. I.I. Dedu. 1989 ... Ecological dictionary

macrophages- A type of lymphocyte that provides nonspecific protection through phagocytosis and participates in the development of the immune response as antigen presenting cells. [English-Russian glossary of basic terms in vaccinology and... ... Technical Translator's Guide

- (from macro... and...phage) (polyblasts), cells of mesenchymal origin in animals and humans, capable of actively capturing and digesting bacteria, cell debris and other particles foreign or toxic to the body (see Phagocytosis)... ... Encyclopedic Dictionary

- (see macro... + ...phage) connective tissue cells of animals and humans, capable of capturing and digesting various particles foreign to the body (including microbes); And. And. Mechnikov called these cells macrophages, in contrast to... ... Dictionary of foreign words of the Russian language

macrophages- ів, pl. (one macroph/g, a, h). Cells of healthy tissue of created organisms, which accumulate and poison bacteria, lattices of dead cells and other foreign or toxic particles for the body. Placenta/rni macrophages/hy macrophages, what... ... Ukrainian Tlumach Dictionary

Books

• Placental macrophages. Morphofunctional characteristics and role in the gestational process, Pavlov Oleg Vladimirovich, Selkov Sergey Alekseevich. For the first time in the world literature, the monograph collects and systematizes modern information about a little-studied group of human placental cells - placental macrophages. Described in detail...

Our body consists of many cells, and each of them performs its own functions. Understanding the diversity of such particles is not so easy. However, having understood their properties and characteristics, we can draw conclusions about the principles by which the organs and systems of our body function, understand the causes of disturbances in their activity, and even determine how such problems can be eliminated. One of the most important systems of our body is the immune system, and its proper functioning depends on many factors. The activity of the immune system is largely determined by the activity of macrophages, let's talk at www..

Macrophages are special blood cells that are necessary for the normal activity of the body's defenses. From Greek, this term can be translated literally as “big devourer.” In order to understand their role in the implementation of the immune response, it is necessary to understand their origin and structural features.

The production of macrophages begins in the bone marrow; in this organ, dividing stem cells form a cell called a monoblast. Its division results in the birth of a promonocyte, and its direct descendant is the monocyte, also known as a type of white blood cell.

The monocyte is transported from the bone marrow to the blood cells, where it can remain for twelve to twenty-four hours. Next, the monocyte leaves the bloodstream and moves into the tissue. Just at this time, a macrophage is produced from it.

Macrophage cells are actually large in size, although they are not visible to the human eye. Such particles are characterized by an irregular floating shape; their membrane is capable of forming spoonpods.
The nucleus is located directly inside the macrophage; particles of red blood cells and other cells, droplets of fat, various fragments of bacteria, etc. can be found in it. How do they penetrate there?

Main functions of a macrophage

When entering human body foreign objects represented by microbes or foreign bodies, the immune system immediately begins to actively work. Such aggressive particles are attacked by phagocytes. Among these cells are macrophages; they begin to recognize, capture and devour strangers who can threaten the well-being of the entire organism.

Macrophages also effectively destroy dead cells that have ended their existence by apoptosis (programmed, natural, normal death). In addition, macrophages provide some antitumor immunity, since they record the occurrence of human body atypical, cancer cells. Macrophages attack and eat them.

There are several types of macrophages

Macrophages can be classified as tissue phagocytes; they live in different types fabrics. Since alveolar macrophages are located inside the walls of the alveoli of the lungs, such particles effectively clean the air inhaled by a person from all kinds of pollutants and aggressive substances.

Kupffer cells are located inside the liver. These macrophages are responsible for destroying old blood cells.

Histiocytes are a common type of macrophage. These cells can be found in all organs, because they are connective tissue cells that form the framework of almost all structures of the body. In certain cases, histiocytes become true macrophages.

Also among such cells are splenic macrophages; as the name suggests, they are located in the spleen, or more precisely, in its sinusoidal vessels. Such macrophages catch dead cells from the blood and destroy them.

Scientists also identify dendritic cells-macrophages, which are located directly under the mucous membranes, as well as in the skin. Peritoneal macrophages live in the peritoneum. Also known particles of this type are macrophages lymph nodes, which, naturally, are located in the lymph nodes. It is these macrophages that serve as filters that cleanse the lymph.

Macrophages and immunity

Macrophage cells are not only capable of mindlessly destroying aggressive objects, as if splitting them into separate fragments. Such cells also carry out the process of presenting their antigens. And antigens are molecules of aggressive particles, they carry information about their foreignness and cause the appearance of an appropriate protective reaction on the part of the immune system. Antigens are not capable of causing infection or harming the body in any other way, but they are a mark of an alien.

Thanks to this property, the body perceives their appearance as an attack and responds to this with a defensive reaction.

During phagocytiosis, macrophages present the antigens of destroyed enemies, exposing them on the surface of their membranes. In addition, they form cytoxins, which carry data about the destroyed aggressor.

Macrophages provide such invaluable information to lymphocytes. They seem to teach the immune system the correct behavior when a carrier of the same antigen re-enters the body. Thanks to this property, the body is able to maintain full combat readiness in relation to specific aggressive particles.

Macrophages are extremely important cells immunity, which are necessary to fully protect the body from aggressive influences.