When macrophages show specific antigen antigen antigen from a particular lymphocarbon, a large number of activated T cells released in the same way as antibodies by activated B cell antibodies increase.
These T cells are transmitted to circulation and distributed throughout the body, where they are flooded for several months or even more years. T The lymphocyte memory cells are formed in the same way as the B memory B cells are formed in the antibody. In the next aspect, make sure that the emission of T cells activated by the same antigen is much faster than the first response time and much more powerful.
Special Attributes of the T-Lymphocyte System Activated T Cells and Cell-Mediated Immunity
The antigens having a receptor molecule in the surface of Sur are connected by the T cells in the same way as antibodies. These receptor molecules consist of variable units similar to the variable part of the humoral antibody, but the molecular portion of the receptor is significantly attached to the cell membrane. Antigenic cells present T-Lymphocytes, large Histocompetibility Complex (MHC) -E protein, and antigen receptor T cell reactions are extremely antigen and protected against Burger Burglary and antibody reaction from B cells. It is important as an antibody. B lymphocytes recognize intact antigens, and T-lymphocytes react only on antigens when compelling specific molecules are mathematical proteins described on the surface of antigen presentation cells (Picture 34-1).
There are three types of antigen presentation cells: macrophages, B lymphocytes and vedicial cells. Denderative cells are located above the body and are most effective to present antigens to T cells. The MHC protein dissolves the fragment of the peptide of the antigen protein inside the antigen that represents the cells and then transported to the cell surface. There are two types of MHC proteins: MHC I and MCH II. The MHC protein I represents antigens in cytotoxic T cells and MHC II proteins represent antigens in T Helper T cells. The antigen-present antigen-present antigen combines the plasma antibody by combining the receptor molecule on the T cell surface Similarly.
Several Types of T Cells and Their Different Functions
Three important T cell groups are T Herer T cells, cytotoxic T cells and T cell inhibitors. The function of each of these cell types is very different.
Helper T cells are the most common type of T cells in the body. T helper lymphocytes act as regulators of almost all immune functions. It does this by producing a series of protein mediators called lymphokines, which act on other cells in the immune system and in the bone marrow. T helper cells secrete interleukin 2-6, granulocyte-monocyte colony stimulating factor and interferon-g. Without the lymphokines produced by helper T cells, the rest of the immune system is almost paralyzed. It is the helper T cells that are inactivated or destroyed by the human immunodeficiency virus (acquired immunodeficiency syndrome), which rarely completely protect the body from infectious diseases.
Helper T cells perform the following functions:
• Stimulates the growth and proliferation of cytotoxic and inhibitory T lymphocytes through the action of interleukins 2, 4 and 5.
• It mainly stimulates the growth and differentiation of B lymphocytes by the action of interleukins 4, 5 and 6 to form plasma cells and antibodies.
• Activate the macrophage system
• Stimulates the helper T cells themselves. Interleukin-2 has a direct positive feedback effect by stimulating the activation of helper T cells which act as enhancers to enhance cellular immune responses.
Cytotoxic T cells can kill microorganisms by direct attack. For this reason, they are also called killer cells. Toxic T lymphocyte surface receptors bind them well to organisms or cells that contain specific binding antigens. When bound, cytotoxic T lymphocytes secrete a perforating protein called perforin. Perforin literally makes a large hole in the membrane of the attacked cell. These holes upset the osmotic balance of cells and cause cell death. Cytotoxic T cells are especially important for killing virus-infected cells, cancer cells, or transplanted cells.
Suppressor T cells suppress cytotoxicity and helper T cell function. It is believed that these suppressive functions are aimed at regulating the activity of other cells to prevent excessive immune reactions that can cause serious harm to the body.
Book Refrence: Pocket Guyton (twelfth edition)