The human body includes many components that are in a 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 protective forces of the body. The mechanism that protects us from the harmful effects of the environment is immunity. He, like other body systems, has connections with the central nervous system and endocrine apparatus.
The role of immunity in the body
The main function of immunity is protection against foreign substances that penetrate from the environment or are formed endogenously in pathological processes. It performs its action thanks to special blood cells - lymphocytes. Lymphocytes are a type of white blood cell and are constantly present in the human body. Their increase indicates that the system is struggling with 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 includes a set of organs that serve as a barrier to harmful factors. These include:
- skin integument;
- thymus
- spleen;
- The lymph nodes;
- red bone 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.
Cellular immunity
Cellular immunity operates at the level of the smallest body structures. This level of protection includes several different lymphocytes, each of which performs its specific function. All of them come from white
blood cells and occupy the bulk of them. T-lymphocytes got their name due to the place of their occurrence - the thymus.
The thymus gland begins to produce these immune structures during the period of human embryonic development, their differentiation in childhood ends. Gradually, this body ceases to fulfill its functions, and by the age of 15-18 it consists only of adipose tissue. Thymus produces only elements of cellular immunity - T-lymphocytes: helpers, killers and suppressors.
When a foreign agent enters, the body activates its protective systems, that is, immunity. First of all, macrophages begin to struggle with a harmful factor, their function is to absorb antigen. If they can not cope with their task, then the next level of protection is connected - cellular immunity. The first to recognize the antigen are T-killers - killers of extraneous agents. The activity of T-helpers is to help the immune system. They control the division and differentiation of all cells in the body. Another of their functions is the formation of the relationship between the two types of immunity, that is, helping B cells 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 the destruction of antigens located 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, providing this relationship. In addition, type 2 T-helpers are responsible for the production of immunoglobulin E, which is directly associated with allergic reactions of the body.
Increase and decrease in T-helpers in the body
There are special norms for all lymphocytes in the body, their study is called an immunogram. Any deviation, whether it is an increase or a decrease in cells, is considered abnormal, that is, a pathological condition develops. If the T-helpers are lowered, it means that the body's defense system is not able to fully carry out its action. This condition is immunodeficiency and is observed during pregnancy and lactation, after illness, with chronic infections. The extreme manifestation is considered 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 goes from a normal process to a pathological reaction. This condition is observed with allergies.
The relationship of cellular and humoral immunity
As you know, the immune system carries out its protective properties at two levels. One of them acts exclusively on cellular structures, that is, when viruses or abnormal gene rearrangements get in, 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 of 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 value of T-helpers in the immune system
Thanks to the release of interleukins, the immune system develops and protects us from harmful effects. Tumor necrosis factor prevents oncological processes, which is one of the most important functions of the body. All this is done 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 in organizing the protective properties of the body.