Histiocytes (sedentary macrophages), unlike microphages, are long-lived cells, the function of which is to fight against those bacteria, viruses and protozoa that can exist inside the host cell. Macrophages, which are passive in the oral mucosa, are activated during the development of inflammation.

in patients with dental caries and periodontitis, various changes in nonspecific factors of local and systemic immunity were revealed.

Data on the content of lysozyme in the blood serum and saliva of patients with caries are diverse. According to most researchers, the content and activity of blood serum lysozyme during dental caries clearly decreases, and in persons with the most acute course of the disease, the activity of this enzyme decreases significantly. The data of other authors do not confirm the existence of a dependence of the occurrence of dental caries on the content of lysozyme in the blood. The content of lysozyme in saliva, according to a number of researchers, decreases as the activity of the carious process increases, the activity of lysozyme in mixed saliva is significantly reduced in acute caries. Other researchers have revealed an opposite trend: an increase in the titer of lysozyme in saliva in uncomplicated caries.

With periodontitis, the level of lysozyme both in saliva and in the liquid of the dental-gingival pocket of patients decreases by initial stages diseases. In patients with a pronounced exudative process in the periodontal tissues, a high proteolytic activity of saliva and gingival fluid was revealed.

Thus, with dental caries and periodontitis, there is a failure of many factors of nonspecific anti-infectious resistance, especially local, in the oral cavity.

Humoral factors of specific immunity

The formation of a humoral specific protective reaction to the antigen provides the B-link immune system.

The main humoral factor of local anti-infectious resistance of the oral cavity is IgA antibodies, in particular secretory ones. Sources of IgA saliva are the small and large salivary glands. It is believed that their main protective property is due to the ability to directly act on bacteria, causing their agglutination and mobilization, saliva Ig-A prevents the adhesion of microorganisms, including fungi and viruses, to the surface of the oral mucosa, as well as to the hard tissues of the tooth. In addition, they can limit the formation of colonies and reduce the virulence of infectious agents.

Immunoglobulin A is also of great importance in the regulation of microflora in the oral cavity. its resettlement and entry into tissues. Lack of it in saliva can lead to disturbances in the ratio between the microflora of the oral cavity. especially its conditionally pathogenic forms and microorganisms.

Disruption of the barrier function of IgA secretions can be the cause of many allergic diseases, the development of cellular immune reactions with damage to the mucous membranes.

Cellular factors of specific immunity

Cell-mediated immune responses are carried out by T-lymphocytes, their population is heterogeneous and is represented by cells specialized in functions.

On the surface of the oral mucosa, T-lymphocytes are found only in the fluid of the gingival sulcus. In other areas, they perform their function in their own lamina of the mucous membrane.

It should be noted that in the oral cavity the gum tissue is most saturated with T-lymphocytes. They produce a factor that stimulates the function of osteoclasts, which enhance the resorption of bone tissue of the alveolar process.

Functional anatomy of the temporomandibular joint in the age aspect

The normal function of the temporomandibular joint (TMJ) depends on the correct relationship of the articular surfaces of the bones, the elasticity of the tissues that form the joint, the location and condition of the intra-articular disc, the condition of the cartilage covering the articular surfaces, the functional state of the synovial layer of the capsule and the composition of the synovial fluid, as well as the coordination of work neuromuscular apparatus. Therefore, knowledge of the anatomical features and biomechanics of the TMJ is necessary for a correct understanding of the pathogenesis. various diseases, their prevention, clear diagnosis, rational approach to treatment.

The TMJ has many similarities to other synovial joints, but a number of the following anatomical and functional characteristics distinguish it from other joints:

a) the articular surfaces of the bones are covered with fibrous tissue - fibrous cartilage, not hyaline;

b) the lower jaw contains teeth, their shape and location in the bone affect the nature of the movement of the joints;

c) the left and right joints function together as a whole, and any movement in one of them is reflected in the nature of movement in the other;

d) complete dependence of the intra-articular relationship on the nature of the closure of the dentition (occlusion) and the state of the masticatory muscles;

e) the joint capsule is attached inside the mandibular fossa, and not outside the joint fossa, as in other joints;

g) the presence of an intra-articular disc. TMJ elements (Fig. 25):

head lower jaw;

mandibular fossa of the temporal bone;

articular tubercle of the temporal bone;

posterior articular cone;

intra-articular disc;

joint capsule;

intra- and extra-articular ligaments;

synovial fluid.

The head of the lower jaw. In a newborn, this head is rounded and has almost the same transverse (mediolateral) and anteroposterior dimensions. With age, it gradually lengthens in the transverse direction. From the moment of eruption of milk teeth and up to two years, an increase in the head occurs. After that, the head size stabilizes, which lasts up to six years, when the first permanent tooth appears, after which the head size increases again. In a newborn, an anterior tilt of the head is not yet expressed. With age, the head tilts anteriorly in relation to the neck of the articular process. In infancy, the lower jaw is distal. With the eruption of milk molars and an increase in the height of the bite, further movement of the articular head occurs anteriorly. In the anterior-upper part of the articular head, there is an articular surface covered with cartilage. In a newborn, the head is covered with a thick layer of fibrous connective tissue, and in adults - fibrous cartilage, which becomes thinner with age.

The head of an adult has an ellipsoidal shape, it is elongated in the transverse direction and compressed in the anteroposterior direction, its long (mediolateral) axis is approximately 3 times larger than the anteroposterior one. Both jaw heads do not stand strictly in the frontal plane, and their horizontal long axes are reduced at an angle open anteriorly and coincide with the transverse diameter of the mandibular fossae. The head consists of a thin layer of compact bone, under which is a cancellous substance.

The neck of the lower jaw is narrowed, on its front surface there is a pterygoid fossa, where most of the upper head of the lateral pterygoid muscle. The formation of the pterygoid fossa is observed at the age of 5 years and looks like a narrow, shallow transverse groove. Normally, the articular head transmits pressure through the avascular central part of the intra-articular disc to the posterior slope of the articular tubercle.

Mandibular fossa. Serves as a receptacle for the head of the lower jaw. In a newborn, it is almost flat, rounded. In front, it is not limited by the articular tubercle, and behind there is a well-defined articular cone. The latter protects the tympanic part of the middle ear from the pressure of the articular head. As the articular oo-slide develops, the posterior articular cone atrophies. In a newborn, the mandibular fossa functions fully, since the lower jaw is distally mixed and the articular head is located in its posterior part. The thickness of the bone of the arch of the fossa in a newborn slightly exceeds 2 mm. Further, the depth of the mandibular fossa increases. It's connected with

growth of the zygomatic process of the temporal bone, which forms the articular tubercle and provides a deepening of the glenoid fossa and the separation of the articular surface from the temporal surface of the scales. With age, the glenoid fossa increases mainly in the transverse direction and deepens, which corresponds to changes in the head of the lower jaw and has an ellipsoidal shape. The articular surface is covered with fibrous cartilage.

Across the mandibular fossa, approximately in the distal third, it intersects stony-drum (glaserov) gap and divides the fossa into the anterior - intracapsular part (lying in the joint cavity) and the posterior - extracapsular part (lying outside the joint cavity). Therefore, the intracapsular part is called the glenoid fossa.

The size of the mandibular fossa is 2-3 times larger than the head of the lower jaw, so there is an inconsistency (discrepancy between the sizes of the head and fossa). The incongruence of the articulating surfaces of the joint is leveled out due to the narrowing of the size of the fossa due to the attachment of the joint capsule inside it at the anterior edge of the petrotympanic fissure of the temporal bone, and is also compensated by the articular disc dividing the joint cavity into two chambers, providing a high congruence of the articular surfaces. The articular disc adjoins the articular surfaces and repeats the shape of the head of the lower jaw and the posterior slope of the articular tubercle, increasing the area of \u200b\u200bcontact of the articular surfaces.

Articular tubercle. In a newborn, the articular tubercle is absent, it is only outlined in front of the mandibular fossa. With the growth of the base of the zygomatic process of the temporal bone and the eruption of milk teeth, the size of the articular tubercle gradually increases. At the age of 6-7 years, it is already clearly visible. The articular tubercle in an adult is an ellipsoidal bony elevation in the form of a cylinder of the temporal bone, lying transversely in the posterior part of the zygomatic process of the temporal bone, the long axis of which is directed in the same way as in the mandibular fossa. It has a front slope, a ridge (top) and a rear slope. The articular surfaces are the crest and posterior slope, which are covered with fibrous cartilage.

Intra-articular disc. Shapes and fits between mating surfaces. In a newborn, the articular disc is a soft round-shaped layer, concave from below and convex from above with barely noticeable thickenings in front and behind. Consists of collagen fibers. As the bony formations of the joint form, the disc forms in parallel. Such changes with the disc are aimed at ensuring the congruence of the articular surfaces

stey. The intra-articular disc gradually acquires anterior and posterior thickening and a thin central part. The upper temporal surface of the disc is convex at the back and saddle-shaped at the front, and the lower is concave - it repeats the shape of the head of the lower jaw and creates, as it were, an additional movable fossa.

There are four zones of the disc (Fig. 26):

the front pole of the disc;

intermediate zone - the middle part, the thinnest part with good elasticity and flexibility;

the posterior pole of the disc is thicker and wider than the anterior one;

bilaminar zone ("posterior cushion") - located between the posterior pole of the disc and the capsule of the joint, represented by two ligaments, between which the neurovascular zone is located.

joint, allowing the disc and head to make small anteroposterior movements around the vertical axis.

The disc occupies such a position in the joint cavity that when the head of the lower jaw moves, the greatest pressure falls on the posterior slope and apex of the articular tubercle, and not on the thin bone plate of the upper and posterior part of the mandibular fossa. Thus, the disc is a soft and resilient pad that absorbs the force of chewing pressure. Intra-articular ligaments. Attaching the disc is shown in Fig. 27.

From the front, the front pole of the disc is connected as follows. Top part disk connects to temporal bone anterior disc-temporal ligament. Bottom part the disc connects to the head of the lower jaw by the anterior disc-maxillary ligament. They are rectangular in shape. The connection of the anterior pole of the disc with the joint capsule is very important in understanding intra-articular changes. From the outer side of the capsule, fibers of the upper head of the lateral pterygoid muscle are woven into its anteromedial surface. Some of these fibers are directly attached to the anteromedial surface of the intra-articular disc.

The posterior zone of disc attachment - the bilaminar zone - is represented by two ligaments. The superior ligament is composed of elastin and is attached posteriorly to the tympanic temporal bone, this is the posterior disc-temporal ligament. When the articular head and disc are displaced forward, it is pulled

and acts as a force opposite to the force of contraction of the lateral pterygoid muscle, and when the mouth is closed, it returns the meniscus to its original position. The lower ligament consists of collagen and is attached behind and below the articular head - the posterior disco-maxillary ligament. When the articular head and disc are displaced forward, it moves forward along with them to a certain state, after which it prevents this displacement.

Between the upper and lower layers of the bilaminar zone, there is a zone rich in blood vessels and nerves. On a sagittal section, the bilaminar zone has the shape of a trapezoid, the larger base of which is at the joint capsule, and the smaller one is at the articular disc. When the head is displaced forward together with the disc, the bilaminar zone is filled with blood, thereby filling the space vacated by the head. As the head with the disc returns to its original state, the bilaminar zone contracts and becomes free of blood. This periodicity is called the physiological process of hemodynamics.

Joint capsule. It defines the anatomical and physiological limits of the TMJ. The articular capsule is an elastic connective tissue "bag", which encloses the articular surfaces of the articulating bones, and connects to the disc along its perimeter. Looks like a "funnel" tapering downward. The attachment of the capsule to the temporal bone is, as it were, shifted anteriorly in relation to the mandibular fossa. Posteriorly, it is attached along the anterior edge of the petrotympanic (glaze) fissure and divides the mandibular fossa into anterior intracapsular and posterior extracapsular parts. The capsule also surrounds the articular surface of the lower jaw head. It is characterized by high strength and elasticity and does not break with complete dislocation of the joint.

Consists of two layers: outdoor, represented by fibrous connective tissue, and internal - endothelial (synovial layer). The cells of the synovial membrane produce synovial fluid, which is the main substrate for the trophism of the articular cartilage.

Synovial fluid. Functions of the synovial fluid:

locomotive - provides free sliding of the articular surfaces;

metabolic - takes part in the process of exchange between the cavities of the joint and vessels, as well as in the movement and enzymatic decay of cells with their subsequent removal from the joint cavity along the lymphatic bed;

trophic - provides nutrition to the avascular layers of the articular disc, articular surfaces and other elements of the joint;

- protective - takes part in the elimination of foreign cells and substances that penetrate from the blood, in case of damage to the joint capsule, etc.

The synovium forms folds in the anterior and posterior surfaces of the joint. Depending on the movement forward or backward, the folds are straightened. So, when the head and disk move forward, folds are formed in the front, and straighten out at the back. When the head and disk move backwards, vice versa.

In the region of the bilaminar zone, the cells of the synovial membrane form outgrowths, the so-called villi, which are the sites of interoreception. Depending on the age, the number and location of them is different. A newborn has no villi. A small number of them appear at the age of 1-2 years and increase by 3-6 years of a child's life. At the age of 16-18 there are already a lot of them. As the body ages, villi involution occurs.

The joint capsule is strengthened from all sides by ligaments. Ligaments are divided into intra- and extracapsular.

Intracapsular ligaments are inside the joint. There are six of them: anterior, posterior, lateral and medial discocular; anterior and posterior disc-temporal. They are described above.

Extracapsular ligaments. The strongest of the extracapsular ligaments is lateral ligament. It adheres to the joint capsule and intertwines with it on its lateral surface (Fig. 28, a). The ligament originates from the posterior part of the zygomatic process of the temporal bone lateral to the articular process and goes obliquely fan-shaped backward and downward (tapering), attaching below and behind the lateral pole of the articular head. On its way, it gives horizontal deep fibers to the capsule. The main biomechanical function of this ligament is to suspend or restrict the movements of the head-disc complex and to limit the displacement of the lower jaw back to the posterior condylar structures of the bilaminar zone. It also regulates the lateral and sagittal movements of the lower jaw. This is the most important link.

Wedge-mandibular ligament (Fig. 28, b) is somewhat spaced from the medial surface of the capsule, starting from the angular spine of the sphenoid bone and attaching to the tongue of the lower jaw. Limits lateral and posterior displacement of the lower jaw.

Stylomandibular ligament far from the joint, starts from the styloid process and attaches to the corner of the lower jaw. Limits forward movement of the lower jaw.

Below is the mechanism of articular changes, which allows the lower jaw to perform the full range of its inherent movements.

When vertical movements (opening the mouth) (Fig. 29) in the initial phase, the head rotates around the horizontal axis in the lower part of the joint (when opening the mouth up to 2 cm). Then these movements are combined with translational ones in the upper section, where the articular heads, together with the discs, begin to move forward and downward, sliding along the posterior slope of the articular tubercle (opening the mouth up to 5 cm). At the end of the path, when the heads reach the extreme position, only rotational movements around the horizontal axis in the lower section occur again.

The ligaments are composed of fibrous inelastic connective tissue, which prevents the joint capsule from stretching during the normal range of motion of the lower jaw. In case of overstretching of the ligaments, their original length is not restored.

TMJ has very complex system innervation and blood supply.

Innervation of the TMJ. The innervation of the joint is carried out by various nerves. The anterior part of the joint is innervated by the masticatory, posterior deep temporal and lateral pterygoid nerves. The outer part is innervated by the chewing and ear-temporal nerves. The inner and posterior surfaces are innervated by the ear-temporal nerve. Branches that take part in the innervation of the joint extend from the perivascular plexuses.

Blood supply to the TMJ. The main sources of blood supply to the joint are the two main arteries (maxillary and superficial temporal) and their numerous branches.

Biomechanics of the temporomandibular joint

The movements in the temporomandibular joint in a newborn and an adult are different From the moment of birth to 7-8 months. the child's life is dominated by the sagittal movements of the lower jaw associated with the act of sucking. This type of movement in the temporomandibular joint is due to its structure in a newborn and is provided by sliding the rounded articular head together with the disc along a fairly flat fossa. As the milk teeth erupt and the articular tubercles develop, biting, chewing, lateral movements of the lower jaw appear.

Extending the lower jaw forward (sagittal movements) with closed teeth from the position of the central occlusion to the anterior one, in most cases, it is guided by the surfaces of the occlusion of the anterior teeth. During sagittal movements, the heads move down and forward along the slopes of the articular tubercles. When moving down, the heads also make rotational movements in the lower part of the joint, forcing the lower jaw to make opening movements dictated by the guiding slopes of the anterior teeth (Fig. 30).

The ability of the heads to move forward along with the disc along the articular slopes and simultaneously rotate in the lower region allows the lower jaw to follow the sagittal incisal path (this is the path that the lower incisors pass along the palatal surfaces of the upper incisors when the lower jaw moves from the central occlusion to the anterior),while the back teeth are open (de-occlusion). At the end of the sagittal articular path (this is the path that the heads go down and forward along the posterior slope of the articular tubercle), when moving from the anterior occlusion to the extreme anterior position, rotational movements around the horizontal are added to the translational movements in the upper section

Humoral factors of non-specific protection

The main humoral factors of nonspecific defense of the body include lysozyme, interferon, the complement system, properdin, lysines, lactoferrin.

Lysozyme refers to lysosomal enzymes, it is found in tears, saliva, nasal mucus, secretions of mucous membranes, blood serum. It has the ability to lyse live and killed microorganisms.

Interferons are proteins with antiviral, antitumor, immunomodulatory effects. Interferon acts by regulating the synthesis of nucleic acids and proteins, activating the synthesis of enzymes and inhibitors that block the translation of viral and - RNA.

The complement system (a complex protein complex that is constantly present in the blood and is an important factor in immunity) is referred to as non-specific humoral factors. The complement system consists of 20 interacting protein components that can be activated without the participation of antibodies, form a membrane-attacking complex, followed by an attack of a foreign membrane bacterial cellleading to its destruction. In this case, the cytotoxic function of complement is activated directly by a foreign invading microorganism.

Properdin takes part in the destruction of microbial cells, neutralization of viruses and plays a significant role in nonspecific activation of complement.

Lysines are serum proteins that have the ability to lyse some bacteria.

Lactoferrin is a factor of local immunity that protects the epithelial integument from microbes.

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Humoral factors of nonspecific defense of the body include normal (natural) antibodies, lysozyme, properdin, beta-lysines (lysines), complement, interferon, inhibitors of viruses in serum and a number of other substances that are constantly present in the body.

Antibodies (natural). In the blood of animals and humans, which have never been sick and have not been immunized before, substances are found that react with many antigens, but in low titers, not exceeding a dilution of 1:10 ... 1:40. These substances have been called normal or natural antibodies. They are believed to result from natural immunization with various microorganisms.

Lizosomal enzyme is present in tears, saliva, nasal mucus, secretions of mucous membranes, blood serum and extracts of organs and tissues, in milk; a lot of lysozyme in the protein of chicken eggs. Lysozyme is resistant to heat (inactivated by boiling), has the ability to lyse live and killed mainly gram-positive microorganisms.

The method for the determination of lysozyme is based on the ability of serum to act on a culture of micrococcus lysodecticus grown on slanting agar. A daily culture suspension is prepared according to an optical standard (10 U) in saline. The test serum is sequentially diluted with physiological solution 10, 20, 40, 80 times, etc. An equal volume of microbial suspension is added to all test tubes. The tubes are shaken and placed in a thermostat for 3 hours at 37 ° C. The reaction is taken into account according to the degree of clarification of the serum. The lysozyme titer is the last dilution in which the complete lysis of the microbial suspension occurs.

SECRETARY IMMUNO GLOBULIN A. Constantly present in the contents of secretions of mucous membranes, milk and salivary glands, in the intestinal tract; possesses pronounced antimicrobial and antiviral properties.

P roperdin (from Latin pro and perdere - to prepare for destruction). Described in 1954 as a polymer as a factor of nonspecific protection and cytolysin. It is present in normal blood serum in an amount up to 25 μg / ml. It is a whey protein (beta globulin) with a molecular weight

220,000. Properdin takes part in the destruction of microbial cells, neutralization of viruses. Properdin acts as part of the properdin system: properdin complement and divalent magnesium ions. Native properdin plays a significant role in nonspecific activation of complement (an alternative pathway of activation).

L and z and s. Serum proteins with the ability to lyse (dissolve) some bacteria and erythrocytes. The blood serum of many animals contains beta-lysines, which cause lysis of the hay bacillus culture, as well as many pathogenic microbes.

Laktoferrin. Non-heminic glycoprotein with iron-binding activity. Binds two ferric atoms to compete with microbes, thereby inhibiting microbial growth. It is synthesized by polymorphonuclear leukocytes and aciniform cells of the glandular epithelium. It is a specific component of the secretion of the glands - salivary, lacrimal, milk, respiratory, digestive and urinary tracts. Lactoferrin is a factor of local immunity that protects the epithelial integument from microbes.

Composition. A multicomponent system of proteins in blood serum and other body fluids, which play an important role in maintaining immune homeostasis. It was first described by Buchner in 1889 under the name "alexin" - a thermolabile factor, in the presence of which microbial lysis occurs. The term "complement" was introduced by Ehrlich in 1895. Complement is not very stable. It was noted that specific antibodies in the presence of fresh blood serum are capable of causing hemolysis of erythrocytes or lysis of a bacterial cell, but if the serum is heated at 56 "C for 30 minutes before the reaction, then lysis will not occur. It turned out that hemolysis (lysis) occurs after due to the presence of complement in fresh serum The greatest amount of complement is found in serum guinea pig.

The complement system consists of no less than nine different serum proteins, designated C1 to C9. C1, in turn, has three subunits - Clq, Clr, Cls. The activated form of complement is indicated by a dash above (c).

There are two ways of activation (self-assembly) of the complement system - classical and alternative, which differ in triggering mechanisms.

With the classical pathway of activation, the complement component C1 binds to immune complexes (antigen + antibody), where subcomponents (Clq, Clr, Cls), C4, C2, and C3 are successively included. The complex of C4, C2 and C3 ensures the fixation of the activated C5 component of the complement on the cell membrane, and then turns on through a series of reactions C6 and C7, which contribute to the fixation of C8 and C9. The result is damage to the cell wall or lysis of the bacterial cell.

In an alternative way of complement activation, viruses, bacteria or exotoxins themselves serve as activators. Components C1, C4 and C2 are not involved in the alternative activation pathway. Activation begins from the C3 stage, which includes a group of proteins: P (properdin), B (proactivator), proactivator convertase C3 and inhibitors j and N. Properdin stabilizes C3 and C5 convertases in the reaction, therefore this activation pathway is also called the properdin system. The reaction begins with the addition of factor B to C3, as a result of a series of sequential reactions, P (properdin) is incorporated into the complex (convertase C3), which acts as an enzyme on C3 and C5, "and the complement activation cascade begins with C6, C7, C8 and C9, which leads to damage to the cell wall or cell lysis.

Thus, the complement system serves as an effective defense mechanism of the body, which is activated as a result of immune responses or through direct contact with microbes or toxins. Let us note some biological functions of activated complement components: they participate in the regulation of the process of switching immunological reactions from cellular to humoral and vice versa; Cell-bound C4 promotes immune attachment; C3 and C4 enhance phagocytosis; C1 and C4, by binding to the surface of the virus, block the receptors responsible for the introduction of the virus into the cell; СЗа and С5а are identical to anaphylactoxins, they act on neutrophilic granulocytes, the latter secrete lysosomal enzymes that destroy foreign antigens, provide directed migration of macrophages, cause contraction smooth musclesincrease inflammation.

It has been found that macrophages synthesize C1, C2, C3, C4 and C5; hepatocytes - C3, Co, C8; cells of the liver parenchyma - C3, C5 and C9.

Interferon. Separated in 1957. English virologists A. Isaacs and I. Linderman. Interferon was originally considered an antiviral defense factor. Later it turned out that this is a group of protein substances, the function of which is to ensure the genetic homeostasis of the cell. In addition to viruses, bacteria, bacterial toxins, mitogenes, etc. act as inducers of interferon formation. Depending on the cellular origin of interferon and factors inducing its synthesis, a-interferon is distinguished, or leukocyte, which is produced by leukocytes treated with viruses and other agents; (3-interferon, or fibroblast, which is produced by fibroblasts treated with viruses or other agents. Both of these interferons are classified as type I. Immune interferon, or y-interferon, produces lymphocytes and macrophages activated by non-viral inductors.

Interferon takes part in the regulation of various mechanisms of the immune response: it enhances the cytotoxic effect of sensitized lymphocytes and K-cells, has an anti-proliferative and antitumor effect, etc. Interferon has a tissue-specificity, that is, it is more active in the biological system in which it is produced, protects cells from viral infection only if it acts on them before contact with the virus.

The process of interaction of interferon with sensitive cells includes several stages: adsorption of interferon on cell receptors; induction of an antiviral state; development of viral resistance (filling of interferon-induced RNA and proteins); pronounced resistance to viral infection. Consequently, interferon does not directly interact with the virus, but prevents the penetration of the virus and inhibits the synthesis of viral proteins on cellular ribosomes during the replication of viral nucleic acids. Interferon also has radiation-protective properties.

I n g and b and to r s. Non-specific antiviral substances of a protein nature are present in normal native blood serum, secretions of the epithelium of the mucous membranes of the respiratory and digestive tracts, in extracts of organs and tissues. They have the ability to suppress the activity of viruses in the blood and fluids outside the sensitive cell. Inhibitors are subdivided into thermolabile (lose their activity when the blood serum is heated to 6O ... 62 ° C for 1 hour) and thermostable (withstand heating up to 100 ° C). Inhibitors have universal neutralizing and antihemagglutinating activity against many viruses.

Inhibitors of tissues, secretions and excretions of animals have been found to be active against many viruses: for example, secretory inhibitors of the respiratory tract have antihemagglutinating and virus neutralizing activity.

Serum bactericidal activity (ALS). Fresh human and animal blood serum has pronounced bacteriostatic properties against a number of infectious agents. The main components that inhibit the growth and development of microorganisms are normal antibodies, lysozyme, properdin, complement, monokines, leukins and other substances. Therefore, ALS is an integrated expression of the antimicrobial properties of humoral nonspecific defense factors. ALS depends on the health status of animals, the conditions of their keeping and feeding: with poor keeping and feeding, the activity of the serum is significantly reduced.

1. « Complement"- a complex of protein molecules in the blood that destroy cells or mark them for destruction (from Lat. Complementum-addition). Various fractions (particles) of complement circulate in the blood, denoted by the symbols C1, C2, C3 ... C9, etc. Being in a disconnected state, they are inert complement precursor proteins. The assembly of complement fractions into a single whole occurs when pathogenic microbes are introduced into the body. Once formed, the complement looks like a funnel and is able to lyse (destroy) bacteria or mark them for destruction by phagocytes.

Have healthy people the level of complement varies slightly, but in patients it can rise or fall sharply.

2. Cytokines - small peptide information molecules interleukins and interferons... They regulate intercellular and intersystemic interactions, determine cell survival, stimulation or suppression of their growth, differentiation, functional activity and apoptosis (natural death of body cells). Ensure the coherence of the immune, endocrine and nervous systems under normal conditions and with pathology.

The cytokine is released onto the surface of the cell (in which it was located) and interacts with the receptor of a nearby other cell. Thus, a signal is transmitted to trigger further reactions.

a) Interleukins(INL or IL) is a group of cytokines synthesized mainly by leukocytes (for this reason, the ending "-leukin" was chosen). Also produced by monocytes and macrophages. There are different classes of interleukins from 1 to 11, etc.

b) Interferons (INF)These are low molecular weight proteins containing a small amount of carbohydrates (from English interfere with reproduction). There are 3 serological groups α, β and γ. α-INF is a family of 20 polypeptides produced by leukocytes, β-INF is a glycoprotein produced by fibroblasts. γ - INF is produced by T-lymphocytes. Differing in structure, they have the same mechanism of action. Under the influence of the infectious principle, the concentration of INF is secreted by many cells at the site of the entrance gate of infection in a matter of hours. Its protective effect against viruses is reduced to inhibiting the replication of RNA or DNA. IFN type I bound to healthy cells protects them from viral penetration.

3. Opsonins these are acute phase proteins. Enhance phagocytic activity, settle on phagocytes and facilitate their binding to a / g coated with immunoglobulin (IgG and IgA) or complement .

Immunogenesis

Antibody formation is called immunogenesis and depends on the dose, frequency and route of administration of a / g.

Cells that provide an immune response are called immunocompetent, and originate from hematopoietic stem cell which are formed in the red bone marrow. Leukocytes, platelets and erythrocytes, as well as precursors of T and B - lymphocytes, are also formed there.

Along with the above cells, the precursors of T and B lymphocytes are cells of the immune system. For maturation, T - lymphocytes are sent to the thymus.

B - lymphocytes, initial maturation takes place in the red bone marrow, and maturation is completed in the lymphatic vessels and nodes. B - lymphocytes comes from the word "bursa" - a bag. In the pouch of Fabritius, birds develop cells similar to human B-lymphocytes. In humans, the organ forming B - lymphocytes was not found. T and B - lymphocytes are covered with villi (receptors).

The storage of T - and B - lymphocytes is carried out in the spleen. This entire process takes place without the introduction of an antigen. The renewal of all blood and lymph cells occurs constantly.

The Jg formation process can be continued if a / r penetrates into the body.

In response to the introduction of a / g, macrophages react. They determine the foreignness of a / g, then phagocytose and if the macrophages failed, the formed histocompatibility complex (MHC) (a \\ r + macrophage), this complex secretes the substance interleukin I (INL I) order, this substance acts on T - lymphocytes, which differentiate into 3 types of Tk (killers), Th (T-helpers), Ts (T-suppressors).

Th allocate INL II order, which acts on the conversion of B - lymphocytes and activation of Tk. After such activation, B - lymphocytes are transformed into plasma cells, from which Jg is ultimately obtained (M, D, G, A, E,).

The Jg production process occurs when a person becomes ill for the first time.

If re-infection with the same microbe occurs, the Jg production pattern is reduced. In this case, the remaining JgG on B - lymphocytes bind immediately to a / r and are transformed into plasma cells. T - the system remains, not involved. Simultaneously with the activation of B - lymphocytes during re-infection, a powerful complement assembly system is activated.

Tk have antiviral protection. Responsible for cellular immunity: they destroy tumor cells, transplanted cells, mutated cells of their own body, HRT is involved. Unlike NK cells, killer T cells specifically recognize a specific antigen and only kill cells with that antigen.

NK-cells. Natural killers, natural killers (eng. Natural killer cells (NK cells)) - large granular lymphocytes with cytotoxicity against tumor cells and cells infected with viruses. NK cells are considered as a separate class of lymphocytes. NKs are one of the most important components of cellular innate immunity, they provide nonspecific protection. They do not have T cell receptors, CD3, or surface immunoglobulins.

Ts - T-suppressors (english regulatory T cells, suppressor T cells, Treg) or regulatory T-lymphocytes. Their main function is to control the strength and duration of the immune response through the regulation of the function of T-helpers and T k. At the end of the infectious process, it is necessary to stop the transformation of B - lymphocytes into plasma cells, Ts suppress (inactivate) the production of B - lymphocytes.

Specific and non-specific factors immune defense always act simultaneously.

Drawing of a diagram of the production of immunoglobulins

Antibodies

Antibodies (a \\ t) are specific blood proteins, another name for immunoglobulins, which are formed in response to the introduction of a / g.

A / t associated with globulins, and changed under the action, a \\ g are called immunoglobulins (J g), they are divided into 5 classes: JgA, JgG, JgM, JgE, JgD. All of them are needed for the immune response. JgG has 4 subclasses JgG 1-4. . This immunoglobulin makes up 75% of all immunoglobulins. Its molecule is the smallest, therefore it crosses the mother's placenta and provides natural passive immunity of the fetus. When primary disease JgG is formed and accumulated. At the onset of the disease, its concentration is low, with the development of the infectious process and the amount of JgG increases, with recovery, the concentration decreases and remains in a small amount in the body after the illness, providing immunological memory.

JgМ the first to appear during infection and immunization. They have a high molecular weight (the largest molecule). Formed by household repeated infection.

JgА contained in the secretions of the mucous membranes of the respiratory tract and digestive tract, as well as in colostrum, saliva. Participate in antiviral protection.

JgЕ responsible for allergic reactions, participate in the development of local immunity.

JgД found in small amounts in human serum, has not been studied enough.

Jg structure

The simplest JgЕ, JgД, JgА

Active centers bind to a / r, the valence of a / r depends on the number of centers. Jg + G are divalent, JgM is 5-valent.