Who discovered cellular and humoral immunity? Mechanisms, determination of humoral immunity tests

Specific immune protection is mainly provided by lymphocytes, which carry out this in two ways: cellular or humoral. Cellular immunity is provided by immunocompetent T-lymphocytes, which are formed from stem cells migrating from the red bone marrow to the thymus. , T-lymphocytes create the majority of lymphocytes in the blood itself (up to 80%), and also settle in the peripheral organs of immunogenesis (primarily in the lymph nodes and spleen), forming thymus-dependent zones in them, which become active points proliferation (reproduction) of T-lymphocytes outside the thymus. Differentiation of T lymphocytes occurs in three directions. The first group of daughter cells is capable of reacting with it and destroying it when it encounters a “foreign” protein-antigen (the causative agent of the disease, or its own mutant). Such lymphocytes are called T-killers (“killers”) and are characterized by the fact that they are capable of on our own, without preliminary immunization and without connecting antibodies and protective complement of the blood plasma (for the interpretation of these concepts, see below), carry out lysis (destruction by dissolving cell membranes and protein binding) of target cells (carriers of antigens). Thus, T-killers are a separate branch of differentiation of stem cells (although their development, as will be described below, is regulated by G-helpers) and are intended to create, as it were, a primary barrier in the antiviral and antitumor immunity of the body.

The other two populations of T-lymphocytes are called T-helpers and T-suppressors and carry out cellular immune protection through regulation of the level of functioning of T-lymphocytes in the humoral immune system. T-helpers (“helpers”), in the event of the appearance of antigens in the body, contribute to the rapid proliferation of effector cells (executors immune defense). There are two subtypes of helper cells: T-helper-1, which secrete specific interleukins type 1L2 (hormone-like molecules) and interferon-β and are associated with cellular immunity (promote the development of T-helpers) T-helper-2 secrete interleukins type IL 4-1L 5 and interact predominantly with T-lymphocytes of humoral immunity. T-suppressors are able to regulate the activity of B and T lymphocytes in response to antigens.

Humoral immunity

Humoral immunity provide lymphocytes that differentiate from brain stem cells not in the thymus, but in other places (in small intestine, lymph nodes, pharyngeal tonsils, etc.) and are called B lymphocytes. Such cells make up up to 15% of all leukocytes. Upon first contact with an antigen, T-lymphocytes that are sensitive to it multiply intensively. Some of the daughter cells differentiate into immunological memory cells and, at the level of lymph nodes in the £-zones, turn into plasma cells, then they are capable of creating humoral antibodies. T-helpers contribute to these processes. Antibodies are large protein molecules that have a specific affinity for a particular antigen (based on chemical structure corresponding antigen) and are called immunoglobulins. Each immunoglobulin molecule is composed of two heavy and two light chains interconnected by disulfide bonds and capable of activating cell membranes of antigens and attaching complement to them (contains 11 proteins capable of lysis or dissolution of cell membranes and binding cell-antigen proteins) . Blood plasma complement has two activation pathways: classical (from immunoglobulins) and alternative (from endotoxins or toxic substances and from medications). There are 5 classes of immunoglobulins (Ig): G, A, M, D, E, differing in functional characteristics. So, for example, lg M usually the first to be included in the immune response to an antigen, activates complement and promotes the absorption of this antigen by macrophages or cell lysis; lg A is located in the cities of the most likely penetration of antigens (lymph nodes gastrointestinal tract, in lacrimal, salivary and sweat glands, in adenoids, in mother’s milk, etc.) which creates a strong protective barrier, promoting phagocytosis of antigens; lg D promotes the proliferation (reproduction) of lymphocytes during infections, T-lymphocytes “recognize” antigens with the help of gammaglobulin included in the membrane, forming an antibody, connecting links, the configuration of which corresponds to the three-dimensional structure of antigenic deterministic groups (haptens or low molecular weight substances that can bind to proteins antibodies, transferring to them the properties of antigen proteins), like a key corresponds to a lock (G. William, 2002; G. Ulmer et al., 1986). Activated antigen B-i T-lymphocytes multiply quickly, become involved in the body’s defense processes and die en masse. At the same time, not many of the activated lymphocytes turn into B and T cells memories that have long term life and during repeated infection of the body (sensitization), memory B and T cells “remember” and recognize the structure of antigens and quickly turn into effector (active) cells and stimulate plasma cells of the lymph nodes to produce the appropriate antibodies.

Repeated contacts with certain antigens can sometimes give hyperergic reactions, accompanied by increased capillary permeability, increased blood circulation, itching, bronchospasm, etc. Such phenomena are called allergic reactions.

Nonspecific immunity, caused by the presence of “natural” antibodies in the blood, which often arise when the body comes into contact with intestinal flora. There are 9 substances that together form a protective complement. Some of these substances are capable of neutralizing viruses (lysozyme), others (C-reactive protein) suppress the vital activity of microbes, others (interferon) destroy viruses and suppress the reproduction of their own cells in tumors, etc. Nonspecific immunity is also caused by special cells - neutrophils and macrophages, capable of phagocytosis, i.e. to the destruction (digestion) of foreign cells.

Specific and nonspecific immunity is divided into congenital (transmitted from the mother), and acquired, which is formed after past illness in the process of life.

In addition, there is the possibility of artificial immunization of the body, which is carried out either in the form of vaccination (when a weakened pathogen is introduced into the body and this causes activation protective forces before the formation of the corresponding antibodies), or in the form of passive immunization, when they do the so-called vaccination against certain disease by introducing serum (blood plasma that does not contain fibrinogen or its coagulation factor, but has ready-made antibodies against a specific antigen). Such vaccinations are given, for example, against rabies, after bites of poisonous animals, and so on.

As V.I. Bobritskaya (2004) testifies, in the blood there are up to 20 thousand of all forms of leukocytes in 1 mm3 of blood, and in the first days of life their number grows, even up to 30 thousand in 1 mm3, which is associated with the resorption of hemorrhage breakdown products in the baby's tissue, which usually occur at birth. After 7-12 first days of life, the number of leukocytes decreases to 10-12 thousand per mm3, which remains the same during the first year of the child’s life. Further, the number of leukocytes gradually decreases and at 13-15 years of age it is set at the level of adults (4-8 thousand in 1 mm 3 of blood). In children of the first years of life (up to 7 years), lymphocytes are exaggerated among leukocytes, and only at 5-6 years their ratio levels out. In addition, children under 6-7 years old have a large number of immature neutrophils (young, rods - nuclear), which causes the relatively low protective forces of the body of children younger age against infectious diseases. Ratio various forms leukocytes in the blood is called the leukocyte formula. With age in children leukocyte formula(Table 9) changes significantly: the number of neutrophils increases while the percentage of lymphocytes and monocytes decreases. At 16-17 years of age, the leukocyte formula takes on a composition characteristic of adults.

Invasion of the body always leads to inflammation. Acute inflammation is usually generated by antigen-antibody reactions in which plasma complement activation begins a few hours after immunological damage, reaches its peak after 24 hours, and subsides after 42-48 hours. Chronic inflammation is associated with the influence of antibodies on the T-lymphocyte system and usually manifests itself through age characteristics leukocyte formula

1-2 days and reaches peak after 48-72 hours. At the site of inflammation, the temperature always rises (associated with vasodilation); swelling occurs (with acute inflammation due to the release of intercellular space proteins and phagocytes, with chronic inflammation— infiltration of lymphocytes and macrophages is added); pain occurs (associated with increased pressure in the tissues).

They are very dangerous for the body and often lead to fatal consequences, since the body actually becomes unprotected. There are 4 main groups of such diseases: primary or secondary immune deficiency, dysfunction; malignant diseases, infections immune system. Among the latter, the herpes virus is well known and is spreading threateningly throughout the world, including in Ukraine, the anti-HIV virus or anmiHTLV-lll/LAV, which causes acquired immune deficiency syndrome (AIDS or AIDS). The basis of the clinic is viral damage to the T-helper (Th) chain of the lymphocyte system, which leads to a significant increase in the number of T-suppressor (Ts) and a violation of the Th / Ts ratio, which becomes 2:1 instead of 1:2, resulting in complete cessation production of antibodies and the body dies from any infection.

The human body is protected from harmful elements that destroy health. A complex immune system helps different ways cope with diseases. One of its components – humoral – is a set of special proteins circulating in the blood.

Specific and nonspecific immunity

General immunity human includes cellular protection - this is an option in which foreign elements are destroyed own cells, and the humoral link. These are antibodies found in dissolved form in the blood plasma, on the surface of the mucous membranes, removing pathogenic antigens.

There is a classification that distinguishes the types of immune defense - specific, nonspecific. The first acts against the pathogen certain type– each infection produces its own antibodies upon first contact.

The nonspecific barrier has versatility - it resists a large number viruses and bacteria. This is a barrier that a person receives at the genetic level by inheritance from his parents. The penetration of infection is prevented by:

• skin;
• epithelium of the respiratory system;
• sebaceous, sweat glands;
• mucous membranes of the eyes, mouth, nose;
• gastric juice;
• sperm, vaginal secretion.

What is humoral immunity

Humoral immunity fights antigens with the help of antibody proteins found in body fluids:

• blood plasma;
• mucous membrane of the eyes;
• saliva.

The humoral immune system begins to activate in the womb and is transmitted to the fetus through the placenta. last weeks pregnancy. Antibodies reach the baby from the first months of life through mother's milk. Breastfeeding is an important factor for the development of immune strength.

Humoral immunity can be formed in two ways:

• When encountering an antigen during infection, antibodies remember the carrier and subsequently, the next time they enter the body, they are recognized and destroyed.
• During vaccinations when introducing a weakened harmful element chemical compounds on cellular level They fix the antigen so that at the next meeting they can recognize it and kill it.

How does humoral immunity work?

Antigens, which are in a liquid state, recognize harmful elements in the blood plasma and destroy them - this is the basis of the mechanism of humoral immunity. The order is:

• Lymphocytes encounter foreign antigens.
• The cells move to the organs of the immune system - lymph nodes, bone marrow, spleen, tonsils.
• Antibodies are produced there, which attach to strangers and become their markers.
• Plasma cells see them and destroy them.
• Memory elements are formed that can recognize the infection the next time it appears.

Humoral factors of innate immunity

The basis of innate protection is information transmitted to the child at the gene level. Humoral factors immunity - a set of substances that help resist numerous types of harmful elements that enter the body. These include:

• Mucin - a secretion containing carbohydrates and proteins salivary glands, protecting against toxins and bacteria.
• Cytokines are protein compounds that are produced by tissue cells.
• Lysozyme - found in tear fluid and saliva - is an enzyme that destroys the walls of bacteria.
• Properdin is a blood protein.
• Interferons are pathogen-killing agents that signal the entry of viruses into cells.
• The complement system - proteins that neutralize microorganisms and help identify harmful elements.

Immunity – common name set of actions of the body aimed at protecting its internal environment and constancy of cellular composition. It is conventionally divided into cellular immunity(provided by lymphocytes various types) and humoral immunity, which is realized with the help of antibodies.

Both systems are closely interconnected and operate in a functional community. Each of them contains specific and nonspecific factors that form immunity.

Nonspecific immunity is a set of standard reactions to any foreign agent, regardless of its nature. It is innate and begins to act immediately after the introduction of the agent.

Specific immunity is acquired throughout life. We can say that he continues to work nonspecific immunity for more high level. Antibodies are produced to specific fragments of foreign particles (antigens) and clones of memory cells mature, “remembering” only this specific antigen. They will participate in its destruction during the next infiltration.

Cellular immunity

Non-specific

This type of immunity is due to the fact that many cells have an innate ability for phagocytosis.

Phagocytosis is the act of capturing, absorbing and digesting foreign agents. These include bacteria and viruses, dead, defective or foreign cells. Many substances artificially introduced into the body (for example, tattoo ink) are also subject to phagocytosis.

Cells with phagocytic activity (phagocytes):

• Granulocytes.
• Monocytes.
• Platelets.
• Lymphocytes.

During phagocytosis, a microbial cell or other foreign agent is gradually enveloped in a phagocyte. After this, with the help of proteolytic enzymes located in special structures of the phagocyte (lysosomes), the destruction of the foreign structure occurs. Some of its fragments are fixed on the surface of the phagocyte to begin the formation of a specific component of immunity.

Specific

This link is represented by T-lymphocytes. They are descendants of stem cells that migrate to thymus gland (Latin name thymus organ). In the thymus, lymphocytes mature and receive immunological “education”.

After entering the blood, most of them form blood lymphocytes, the other part settles in lymphoid tissue(lymph nodes and spleen).

style="line-height: 1.5em;">There are three types of T-lymphocytes:

• T-killers are able to independently recognize the carrier of the antigen and destroy it.
• T helper cells stimulate the proliferation of effector cells (providing immunity) when an antigen appears in the body.
• T-suppressors are “observers” of the activity of effectors.

Humoral immunity

This link of immunity is provided by protein systems located in the blood (Latin humor - liquid, moisture).

Non-specific humoral immunity

Non-selective protective properties have following systems body:

• Lysozyme. A protein that inhibits the development of microorganisms and causes their destruction. Contained in saliva, nasal and intestinal mucus, tear fluid. Included in the contents of lysosomes of macrophages.
• Interferon, lysines, plakins. Synthesized by all cells of the body. They have antiviral and antitumor activity.
• C-reactive protein. It is also part of the blood plasma and has a bacteriostatic (suppressing the reproduction and growth of microorganisms) effect.
• Complement system. A system of several types of proteins ( total approximately 20). They are able to settle on the membranes of microorganisms and form a structure that causes the destruction of this membrane.
• Properdin system. In collaboration with the complement system, it is capable of attacking the bacterial membrane.

style="line-height: 1.5em;">Specific humoral immunity

This segment of immunity is represented by antibodies, or immunoglobulins. Antibodies are specific protein formations that have the ability to attach to a specific structure of a bacterium or virus. After fixation, the antibodies attract the complement system of the blood plasma, which causes destruction (lysis) of the foreign structure.

Antibodies are synthesized by B lymphocytes. B lymphocytes “specialize” in lymphoid tissue (intestinal lymph nodes, tonsils and other organs).

They recognize the antigen and begin to produce antibodies that have a chemical affinity for a strictly defined area. This is due to the immunological memory of lymphocytes, preserved after the first encounter with the antigen.

Types of immunoglobulins:

1. Immunoglobulins type A (IgA) are found in all biological fluids (milk, saliva, urine, etc.).
2. IgM are large complexes capable of binding several microbial agents. Appear during an acute infectious process.
3. IgG accompanies the appearance of IgM. They are signs of chronic infection.
4. IgE is responsible for protecting the penetration of toxins through the skin.

The approximate time it takes for B cells to produce sufficient antibodies is 2 weeks.

The immune system is a perfectly regulated mechanism given to humans by nature to protect against external and internal aggression.

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 the growth of 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, tumor cells and infectious agents are destroyed in the human body. Main actor cellular immunity - lymphocytes, the synthesis of which occurs in bone marrow, after which they migrate to the thymus. It is because of their movement into the thymus that they were called T-lymphocytes. If any threat is detected in the body, these immunocompetent cells Quite quickly they 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. T-helpers are the first to know that something has entered the body. foreign protein and release special enzymes in response 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. Humoral and cellular systems The body's defenses 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 participate 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 - skin and mucous membranes, subepithelial tissue, regional The lymph nodes and 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.

Responsible for the safety and normal functioning of organs and systems, protecting them from dangerous agents.

Photo 1. Immunity is responsible for the body’s ability to resist threats. Source: Flickr (Danielle Scruggs)

What is humoral immunity

The humoral immune response involves molecules that are found in the blood. B-lymphocytes play a critical role in its functioning. This differs from cellular immunity, which depends on T lymphocytes.

Note! Humoral immunity is aimed at destroying pathogens that are in the blood and in the extracellular space.

B lymphocytes- these are cells of the immune system that are produced by the liver of the fetus in the womb, and after birth - in the red bone marrow contained in the tubular bones.

Each B lymphocyte has an antigen recognition receptor on its surface. Antigens are any substances that the body views as potentially dangerous. In particular, they are part of pathogenic viruses and bacteria. After contact with antigen B lymphocytes can transform into plasma cells capable of producing immunoglobulins.

Immunoglobulins (antibodies, Ig) are protein compounds that prevent reproduction pathogenic microorganisms and neutralize the toxins they produce.

There are 5 classes of immunoglobulins:

They differ in composition, structure and functions.

How does humoral immunity work?

B lymphocytes are formed from stem cells in the bone marrow. After maturation, they enter the bloodstream. On their surface there are cells that can be separated from lymphocytes and circulate in the blood independently of them.

When an antigen enters the body, immunoglobulin M binds to it and inactivates it. Antibodies trigger a pattern of activation of complement (a complex of complex proteins in the blood, protein enzymes that protect against foreign agents), which leads to the destruction of the pathogen.

Once this happens, the B lymphocytes turn into plasma cells. They begin to produce immunoglobulins of different classes, designed to fight similar antigens.

Antibodies bind pathogens and prevent them from damaging body tissues.

Humoral immune response

The immune reaction, which consists of the activation of B lymphocytes and their production of immunoglobulins, is called the humoral immune response.

Note! The formation of specific antibodies designed to fight specific antigens is main goal immune response. After entering the blood, immunoglobulins provide reliable protection from pathogenic substances and microorganisms.

There are two stages of the humoral immune response:

• inductive - at this stage antigen recognition occurs;
• productive - at this stage, B-lymphocytes turn into plasma cells and secrete antibodies, then immune reactions slow down until they stop completely.

In the productive phase of the humoral immune response, memory cells are formed, which are activated if a repeated encounter with the antigen occurs.

In this case, a secondary immune reaction occurs. It develops in the same way as the primary one, but proceeds much faster.

Cellular immunity

When this type of immunity works, cells of the immune system are activated. The main ones are T-killer cells, natural killer cells and macrophages.

• T-killers- these are cells that fight viruses, intracellular bacteria and cancer cells. They are a type of lymphocyte. Natural killer cells are another type of lymphocyte. They are responsible for fighting viruses and cancer cells.
• Macrophages- These are cells of the immune system that are capable of absorbing and digesting bacteria, the remains of dead cells and other pathogenic particles. This process is called phagocytosis, and the cells that are capable of carrying it out are called phagocytes. Macrophages are a type of phagocyte.
• Cytokines- these are protein molecules that ensure the transfer of information from one immune cell to another. In this way, their activities are coordinated. These molecules are also responsible for coordinating the work of the immune system with the activity of the nervous and endocrine systems. In addition, cytokines can independently suppress viruses.

Note! Cellular immunity is responsible for the destruction of intracellular bacteria, pathogenic fungi, foreign cells and tissues, as well as cancer cells. It fights pathogens that are inaccessible to the humoral immune response.

How does cellular immunity work?

There are nonspecific and specific cellular immunity.

The first involves the capture, engulfment and digestion of pathogens by phagocytes. They gradually envelop the foreign agent, and then destroy it with the help of special enzymes.

T-killer cells, natural killer cells and other lymphocytes are responsible for specific cellular immunity.

The first to come into action are T-helper cells, which trigger the immune response. During the immune response, killer T cells interact with cells infected with viruses and intracellular bacteria, as well as cancer cells, and destroy them.

Natural killer cells, in turn, fight cells that are inaccessible to the action of killer T cells.

After the pathogens are destroyed, T-suppressor cells come into play, suppressing the immune response.