Immunity is nonspecific and specific: mechanisms, difference

Immunity is a word that is almost magical for most people. The fact is that each organism owns its own genetic information, which is peculiar only to it, therefore, each person has different immunity to diseases.

So what is this - immunity?

Surely everyone who is familiar with the school curriculum in biology roughly represents that immunity is the body's ability to protect itself from all alien, that is, to resist the action of harmful agents. And as those that get into the body from the outside (microbes, viruses, various chemical elements), and those that are formed in the body itself, such as dead or cancerous, as well as damaged cells. Any substance that carries alien genetic information is an antigen, which is literally translated - "against genes." Non-specific and specific immunity is ensured by the coherent and coordinated work of the bodies responsible for the production of specific substances and cells capable of recognizing in a timely manner what is for the organism and what is alien, and also adequately responding to the invasion of a foreign one.

Antibodies and their role in the body

The immune system first detects the antigen, and then tries to destroy it. In this case, the body produces specific protein structures - antibodies. It is they who stand up for protection when they get into the body of any pathogen. Antibodies are special proteins (immunoglobulins) produced by leukocytes to neutralize potentially dangerous antigens - microbes, toxins, cancer cells.

By the presence of antibodies and their quantitative expression, it is determined whether the human body is infected or not, and whether it has sufficient immunity (nonspecific and specific) against a specific disease. Having detected these or other antibodies in the blood, one can not only make a conclusion about the presence of an infection or a malignant tumor, but also determine its type. It is on the determination of the presence of antibodies to the causative agents of specific diseases that many diagnostic tests and analyzes are based. For example, with an enzyme-linked immunosorbent assay, a blood sample is mixed with a previously prepared antigen. If a reaction is observed, it means that the body has antibodies to it, therefore, the agent itself.

Types of immune defense

In their origin, the following types of immunity are distinguished: specific and nonspecific. The latter is innate and is directed against any alien substance.

Nonspecific immunity is a complex of protective elements of the body, which, in turn, is divided into 4 types.

1. To mechanical elements (the skin and mucous membranes, eyelashes, sneezing, coughing) are involved.
2. To chemical (acid sweat, tears and saliva, nasal discharge).
3. To the humoral factors of the acute phase of inflammation (complement system, blood coagulation, lactoferrin and transferrin, interferons, lysozyme).
4. To the cellular (phagocytes, natural killers).

Specific immunity is called acquired, or adaptive. It is directed against selected foreign substances and manifests itself in two forms - humoral and cellular.

Specific and nonspecific immunity, its mechanisms

Let us consider the difference between the two types of biological protection of living organisms. Nonspecific and specific mechanisms of immunity are divided by the speed of reaction and action. Factors of natural immunity begin to protect immediately, as soon as the pathogen penetrates through the skin or mucous membrane, and do not conserve memory of interaction with the virus. They work throughout the entire battle with the infection, but especially effectively - in the first four days after the virus has penetrated, then the mechanisms of specific immunity begin to work. The main protectors of the body from viruses during the period of action of nonspecific immunity become lymphocytes and interferons. Natural killers identify and destroy infected cells with the help of secreted cytotoxins. The latter cause the programmed destruction of cells.

As an example, we can consider the mechanism of action of interferon. In viral infection, cells synthesize interferon and secrete it into the space between the cells, where it connects to the receptors of other healthy cells. After their interaction, the cells synthesize two new enzymes: synthetase and protein kinase, the first of which inhibits the synthesis of viral proteins, and the second splits foreign RNA. As a result, a barrier from uninfected cells forms near the focus of the viral infection.

Natural and artificial immunity

Specific and nonspecific innate immunity is divided into natural and artificial. Each of them is active or passive. The natural is acquired by natural means. A natural active appears after a cured illness. For example, people who suffered a plague did not become infected when nursing. Natural passive - placental, colostral, transovarial.

Artificial immunity is revealed as a result of the introduction into the body of weakened or dead microorganisms. Artificial active appears after vaccination. Artificial passive is acquired with the help of serum. When an active organism independently creates antibodies as a result of disease or active immunization. It is more stable and long lasting, can last many years and even a lifetime. Passive immunity is achieved with the help of antibodies that are artificially introduced during immunization. It is less prolonged, it acts a couple of hours after the administration of antibodies and lasts from several weeks to months.

Specific and nonspecific immunity of difference

Nonspecific immunity is also called natural, genetic. This property of the body, which is genetically inherited by representatives of this species. For example, there is human immunity to canine and rat plague. Congenital immunity can be weakened by irradiation or starvation. Nonspecific immunity is realized with the help of monocytes, eosinophils, basophils, macrophages, neutrophils. Specific and nonspecific immunity factors are also different in time of action. Specific manifestation after 4 days in the synthesis of specific antibodies and the formation of T-lymphocytes. This triggers immunological memory due to the formation of T- and B-memory cells for a specific pathogen. Immunological memory is stored for a long time and is the nucleus of a more effective secondary immune action. It is on this property that the ability of vaccines to prevent infectious diseases is based.

Specific immunity is intended to protect the body, which is created in the process of development of an individual organism throughout its life. When penetrating the body of an excessive number of pathogens, it can be weakened, although the disease will proceed in a lighter form.

What is the immunity of a newborn baby?

Only the newly born baby already has non-specific and specific immunity, which gradually, with each passing day, intensifies. During the first months of life, the baby is helped by the presence of the antibodies of the mother, which he received from her through the placenta, and then receives along with breast milk. This immunity is passive, it is not persistent and protects the baby for up to about 6 months. Therefore, the newborn child is immune to such infections as measles, rubella, scarlet fever, parotitis and others.

Gradually, and also with the help of vaccination, the child's immune system will learn how to produce antibodies and to resist the pathogens themselves, but this process is long and very individual. The final formation of the immune system of the child is completed at the age of three. The baby is younger than the immune system is not completely formed, so the baby is more susceptible to most of the bacteria and viruses than the adult. But this does not mean that the newborn's body is completely defenseless, it is able to withstand many infectious aggressors.

Immediately after birth, the baby encounters them and gradually learns to exist with them, producing protective antibodies. Gradually, the microbes colonize the intestines of the baby, dividing into useful ones, which help digestion and the harmful ones, which do not show themselves until the microflora balance is disturbed. For example, microbes settle on the mucous membranes of the nasopharynx and tonsils, in the same place protective antibodies are produced. If the organism already has antibodies against the infection, the disease either does not develop, or passes in a mild form. On this property of the body is the conduct of preventive vaccinations.

Conclusion

It should be remembered that immunity is nonspecific and specific - it is a genetic function, that is, each organism produces the necessary number of different protective factors for it, and if this is enough for one, then for another it does not. And, on the contrary, one entirely can do with the necessary minimum, whereas another person of protective bodies will need much more. In addition, the reactions occurring in the body are quite variable, since the work of the immune system is a continuous process and depends on a variety of internal and external factors.