The human body includes many components that are in constant relationship with each other. The main mechanisms include: respiratory, digestive, cardiovascular, genitourinary, endocrine and nervous systems. In order to protect each of these components, there are special defenses of the body. The mechanism that protects us from the harmful effects of the environment is immunity. It, like other body systems, has connections with the central nervous system and the endocrine apparatus.
The role of immunity in the body
The main function of immunity is protection from foreign substances penetrating from the environment or formed endogenously during pathological processes. It performs its action thanks to special blood cells - lymphocytes. Lymphocytes are a type of leukocytes and are constantly present in the human body. Their increase indicates that the system is fighting a foreign agent, and a decrease indicates a lack of protective forces - immunodeficiency. Another function is the fight against neoplasms, which is carried out through the tumor necrosis factor. The immune system includesthemselves a set of organs that serve as a barrier to harmful factors. These include:
- skin;
- thymus;
- spleen;
- lymph nodes;
- red marrow;
- blood.
There are 2 types of mechanisms that are inextricably linked. Cellular immunity fights harmful particles through T-lymphocytes. These structures, in turn, are divided into T-helpers, T-suppressors, T-killers.
The work of cellular immunity
Cellular immunity operates at the level of the smallest structures of the body. This level of protection includes several different lymphocytes, each of which performs a specific function. All of them originate from white blood cells and occupy the bulk of them. T-lymphocytes got their name due to the place of their origin - the thymus. The thymus begins to produce these immune structures as early as the period of human embryonic development, and their differentiation ends in childhood. Gradually, this organ ceases to perform its functions, and by the age of 15-18 it consists only of adipose tissue. The thymus produces only elements of cellular immunity - T-lymphocytes: helpers, killers and suppressors.
When a foreign agent enters, the body activates its defense systems, that is, immunity. First of all, macrophages begin to fight the harmful factor, their function is to absorb the antigen. If they can't handle theirtask, then the next level of protection is connected - cellular immunity. The first to recognize the antigen are T-killers - killers of foreign agents. The activity of T-helpers is to help the immune system. They control the division and differentiation of all body cells. Another of their functions is the formation of a relationship between two types of immunity, that is, helping B-lymphocytes to secrete antibodies, activating other structures (monocytes, T-killers, mast cells). T-suppressors are needed in order to reduce the excessive activity of helpers, if necessary.
Types of T-helpers
Depending on the function performed, T-helpers are divided into 2 types: the first and second. The former carry out the production of tumor necrosis factor (fight against neoplasms), gamma-interferon (fight against viral agents), interleukin-2 (participation in inflammatory reactions). All these functions are aimed at destroying the antigens inside the cell.
The second type of T-helpers is needed to communicate with humoral immunity. These T-lymphocytes produce interleukins 4, 5, 10 and 13, which provide this relationship. In addition, type 2 T-helpers are responsible for the production of immunoglobulin E, which is directly related to the body's allergic reactions.
Increase and decrease of T-helpers in the body
There are special norms for all lymphocytes in the body, their study is called an immunogram. Any deviation, regardless of whether it is an increase or decrease in cells, is considered abnormal, that is, some kind of pathological develops.condition. If T-helpers are lowered, then the body's defense system is not able to fully carry out its action. This condition is an immunodeficiency and is observed during pregnancy and lactation, after illness, with chronic infections. An extreme manifestation is HIV infection - a complete violation of the activity of cellular immunity. If T-helpers are elevated, then an excessive reaction to antigens is observed in the body, that is, the fight against them passes from a normal process into a pathological reaction. This condition is observed with allergies.
Relationship between cellular and humoral immunity
As you know, the immune system exercises its protective properties at two levels. One of them acts exclusively on cellular structures, that is, when viruses enter or abnormal gene rearrangements, the action of T-lymphocytes is activated. The second level is humoral regulation, which is carried out by affecting the entire body with the help of immunoglobulins. These protection systems in some cases can work separately from each other, but most often they interact with each other. The connection between cellular and humoral immunity is carried out by T-helpers, that is, “helpers”. This population of T-lymphocytes produces specific interleukins, these include: IL-4, 5, 10, 13. Without these structures, the development and functioning of humoral defense is impossible.
The importance of T-helpers in the immune system
Thanks to the release of interleukins, the immune system develops andprotects us from harmful influences. Tumor necrosis factor prevents oncological processes, which is one of the most important functions of the body. All this is carried out by T-helpers. Despite the fact that they act indirectly (through other cells), their importance in the immune system is very important, as they help organize the body's defenses.
