From Big Medical Encyclopedia

INHIBITORS OF VIRUSES (Latin inhibere to hold, stop) — the virusotropny substances which are formed in a human body or an animal and having ability as a result of interaction with viruses to suppress their infectious activity. Besides, And. can suppress also separate functions of viruses, napr, the hemagglutination caused by an influenza virus century. Unlike antibodies (see), the Crimea strict specificity is inherent, inhibitors possess wider range of activity concerning different types of viruses that gave the grounds to call them nonspecific factors of immunity.

For the first time And. were found in blood serum century. In 1910 S. Fleksner and J. Lewis described ability of normal serum of sheep to neutralize a virus of poliomyelitis. In the subsequent inhibitors to various viruses were found in blood sera of monkeys, rabbits, dogs, birds, cows, horses and other animals. In 1942 Mr. Hurst (G. To. Hirst) found inhibitors to an influenza virus in blood serum of the healthy person. Results of a large number of the researches conducted in various laboratories allow to draw a conclusion that serums of the person and animals contain inhibitors, active in relation to many both RNA - and D H K-with to the holding viruses. It is established also, as. century, revealed in blood sera of different animals, differ as it is qualitative, and quantitatively. So, blood serum of the person contains inhibitors of influenza viruses And yes In, but there are no inhibitors of an influenza virus With, serum of rats contains in a large number inhibitors of influenza viruses With, but it is not enough inhibitors of influenza viruses And yes Century.

In addition to specific differences in contents And. century, characteristic of various animals, both individual fluctuations at separate individuals, and changes of quantity are observed And. century at the same animal depending on age and season: contents And. century in serum of laboratory animals sharply decreases in winter and spring months and increases in the summer and in the fall. Similar patterns of age and seasonal dynamics are established also for the person. Blood sera of children of the first 2 — 5 months of life have high virus neutralizing activity (in this case take place And. century of a maternal origin). Then contents And. century sharply falls and up to 1,5 — 2 years blood serum of children is characterized by the low content of inhibitors. Quantity And. begins to increase after 3 years century, reaching high rates by 9 — 10 years. Old men have a contents And. century in blood serum it is also small.

Studying of the chemical nature And. century of various animals and the person allowed to come to conclusion about their heterogeneity and rather complex structure. It turned out, e.g., that virusingibiruyushchy activity of blood serum of a Guinea pig concerning influenza viruses of A and ECHO is connected with the lipoproteids which are a part of globulinovy fraction of proteins of serum, and inhibitor of a virus Sendai was found as a part of albuminous fraction.

Heterogeneity And. caused emergence of various classifications century. Distribution is the basis for one of them And. century by the principle of resistance to warming up at various temperature. So, for inhibitors of myxoviruses and respiratory viruses T. I. The following classification is offered Luzyanina. 1. Thermolabile inhibitors which collapse after warmings up at t ° 62 — 65 ° within an hour (beta inhibitors). Most of them belongs to beta lipoproteids.

2. Thermostable inhibitors which in turn are divided into two groups — inhibitors of moderate heat stability and inhibitors of high heat stability.

And. century of moderate heat stability collapse after warming up at t ° 75 ° within an hour (Fransis's inhibitor, alpha inhibitor). They treat mucoproteins which prosthetic group are neuraminic to - that and its derivatives.

And. century of high heat stability do not collapse at t ° 100 ° (gamma inhibitor). On chemical structure they treat glycoproteins, are preferential connected with alfa2-globulinovy fraction of serums, but are found as well among albuminous and beta globulinovoy fractions.

In addition to blood serum, And. are found also in fabrics, secrets and excretes of the person and vertebrate animals century. They are found in extracts from tissues of a lung, liver, spleen, kidney, brain, in saliva, urine etc. In particular, the inhibitors suppressing a reproduction of a virus of poliomyelitis in various cultures of cells are found in saliva of healthy people. It is necessary to notice that in some cases more complex structure is inherent in the inhibitors emitted from fabrics, than And. century, received from blood sera. It was not succeeded to establish any dependence between the content of inhibitors in blood serum and fabrics.

According to V. M. Zhdanov, P. N. Kosyakov, 3. And. Rovnova, etc., muko-and lipoprotein And. century, revealed in various fabrics, secrets and excretes of an organism, and also some types of thermostable serumal inhibitors should be considered the receptors of cells or substances identical on the structure to these receptors.

Mechanism of action

Mechanism of action And. comes down to their direct coupling century with viruses therefore the last lose ability to be adsorbed on cells and to cause the subsequent development of infectious process. Distinguish two stages of interaction of viruses and inhibitors. The first of them comes to the end with formation of biologically neutral complex. But as a part of this complex the virus still keeps the activity, edges the virus + + can be revealed after processing of a complex «And. century» trypsin. The second stage consists in an irreversible inactivation of the neutralized virus. This stage is irreversible, and reactivation of a virus after destruction of inhibitor does not happen.

In spite of the fact that anti-virus activity And. century sometimes happens rather high (it is shown, e.g., that blood sera of Guinea pigs can neutralize up to 10 million DL50 for mice of some influenza strains), their destiny in the course of the diseases caused by viruses is studied extremely insufficiently. Nevertheless it is established that development of an influenza virus in embryos of hens, in a brain and easy mice leads to falling of credits of inhibitors. It was offered to use the similar decrease in the inhibiting activity of washouts from upper respiratory tracts of the person observed in the acute period of an influenzal infection as a method of early diagnosis of flu. In the course of recovery from a viral infection (in particular, from flu) the amount of inhibitors increases again. At the same time credits of serumal inhibitors begin to accrue approximately in the same terms when also antibodies to viruses appear. Increase in contents And. century and antibodies usually goes in parallel. In the subsequent increase nonspecific And. is replaced by decrease in their quantity century, a cut comes earlier, than the antiserum capacity begins to decrease.

The high anti-virus activity observed by a time And. gave century the grounds for attempts to use them as preventive and to lay down. cure for some experimental viral infections. However despite the received positive takes in a number of such experiments And. did not find practical application in therapy of viral infections century.

Bibliography: P. N. jambs and Exactly in and 3. I. Virus-induced immunity, M., 1972; L at z I am N and N and T. Ya. Features of interaction of thermolabile serumal inhibitors with various viruses, Acta virologica, t. 6, No. 6, page 498, 1962; Problems of a pathogeny and immunology of respiratory viral infections, under the editorship of A. A. Smo-rodintsev, etc., t. 1, page 35, L., 1969.

I. G. Balangding.