The main function of t cells, helper ...

Considered

October 2008 the immune system is composed of many interdependent cell types that collectively protect the body from bacterial, parasitic, fungal, viral infections and the growth of tumor cells. Many of these cell types with specific functions. Cells of the immune system can absorb bacteria, parasites, or to kill tumor cells, or kill viral-infected cells. Often, these cells depend on T helper subset for activation signals as selection formally known as cytokines, lymphokines, or more specifically interleukins. The purpose of this paper is to examine organs, cell types and interactions between cells of the immune system in comments on their importance and interdependence of many auxiliary T. This understanding can help to understand the root of immunodeficiencies, and perceived potential ways that the immune system can be modulated when specific disease. Bone marrow - all immune cells, originally derived from bone marrow. They form through a process called hematopoiesis. In the blood, bone marrow stem cells differentiate into mature cells or immune cells or precursors that migrate from the bone marrow to continue their maturation elsewhere. Bone marrow produces lymphocytes, natural killer cells, granulocytes and immature thymocytes, in addition to red blood cells and platelets. Thymus - thymic function is to produce mature T cells. Immature thymocytes, also known as prothymocytes, leave in the bone marrow and migrate to the thymus. Thanks to the excellent ripening process is sometimes called thymus education, T cells, which are useful for the immune system of living, while T cells that can cause negative autoimmune response eliminated. Mature T cells, then into the blood. The spleen - immune spleen filter blood. It consists of B-cells, T cells, macrophages, dendritic cells, natural killer cells and red blood cells. In addition to the fixation of foreign materials (antigens) in the blood that passes through the spleen, migratory macrophages and dendritic cells bring antigens spleen through the blood. The immune response is initiated when macrophages and dendritic cells present antigen to the appropriate B or T cells. This authority may be regarded as immune Center conference. In the spleen, B cells are activated and produce large amounts of antibodies. In addition, old red blood cells are destroyed in the spleen. Lymph nodes - Lymph nodes act as an immunological filter for biological fluids are known to lymph. Lymph nodes are located throughout the body. It consists mainly of T cells, B lymphocytes, dendritic cells and macrophages, fluid leakage from the sites of most of our fabrics. Antigens filtered from lymph in the lymph nodes before returning to the lymph circulation. Similarly, as the spleen, macrophages and dendritic cells that capture antigens present these materials to foreign T and B cells and thus begin the immune response. T cells - T lymphocytes, usually divided into two subsets that are functionally and fenotypno (identifiably) different. A subset of T-helper cells, also called CD4 + T-cells responsible coordinator of immune regulation. The main function of helper T cells to increase or strengthen the immune response to the selection of specialized factors that activate other white blood cells to fight infection. Another important type of T cells called T killer / podavytel subset or CD8 + T cells. These cells play an important role in the murder directly certain tumor cells, viral-infected cells and sometimes parasites. CD8 + T cells are also important in the down regulation of immune response. Both types of T cells can be found throughout the body. They often depend on the secondary lymphoid organs (lymph nodes and spleen), and areas where activation occurs, but they occur in other tissues, most notably in the liver, lungs, blood, intestines and genital tract. Natural killer cells - natural killer cells, often referred to as the killer, like killer T subset (CD8 + T cells). They function as effector cells that directly kill certain tumors such as melanoma, lymphoma and viral-infected cells, including herpes and cytomegalovirus-infected cells. NK cells, unlike CD8 + (killer) T cells kill their objectives without first "conference" in lymphoid organs. However, NK-cells were activated by secretions from CD4 + T cells will kill their tumor or viral-infected goals more effectively. B cells - the main function of B-lymphocytes are antibody response to foreign proteins of bacteria, viruses and tumor cells. Antibodies specific proteins that specifically recognize and bind to a specific protein that specifically recognize and bind to a specific protein. Production of antibodies and bind to foreign substances or antigens, often is critical as a means of signaling other cells to engulf, kill or remove the substance from the body. Granulocytes or polymorphonuclear (PMN) Leukocytes - Another group of white blood cells together referred to as granulocytes or polymorphonuclear leukocytes (PMNs). Granulocytes consist of three types of cells identified as neutrophils, eosinophils and basophils, depending on their color characteristics of certain dyes. These cells are the most important role in removing bacteria and parasites from the body. They swallow these foreign bodies and degrade them, using its powerful enzymes. Macrophages - macrophages play an important role in regulating the immune response. They are often referred to as scavengers or antigen-presenting cells (APC), because they pick up and ingest foreign material and present their antigens to other immune system cells such as T cells and B cells. This is an important first step in the early immune response. Stimulated macrophages have elevated levels of phagocytosis and also secretory. Dendritic cells - another type of cell, addressed recently is dendritic cells. Dendritic cells, which also occur in the bone marrow function as antigen present cells (APC). Indeed, dendritic cells are more efficient than APC macrophages. These cells are usually found in the structural department of lymphoid organs such as the thymus gland, lymph nodes and spleen. However, they are also in the blood and other body tissues. It is believed that they capture antigen or bring it to lymphoid organs where immune response is initiated. Unfortunately, one of the reasons we know so little about dendritic cells is that they are extremely difficult to distinguish what is often a prerequisite for studying the functional properties of specific cell types. Special issue here recently found that dendritic cells, binds a large number of HIV and may be a reservoir of virus that is transmitted to CD4 + T-cell activation at the event. The immune response to foreign antigen requires antigen-presenting cells (APC), (as a rule, or macrophages and dendritic cells) in combination with B-cells and T cells. When APC presents antigen on the cell surface to the cells, B cells proliferate and produce signals antibodies that specifically bind to this antigen. If the antibodies bind to antigens on the bacteria or parasites, it acts as a signal to PMNs or macrophages to absorb (phagocyted) and kill them. Another important function of antibodies to start a "complement destruction cascade." When antibodies bind to cells and bacteria, serum proteins called application bind to immobilized antibodies and destroy the bacteria by creating holes in them. Antibodies may also signal the natural killer cells and macrophages to kill the virus or bacterial infection of cells. If APC is antigen T cells, T cells are activated. Activated T cells proliferate and become secretory in the case of CD4 + T cells, or, if CD8 + T cells are activated to kill target cells directly expressing the antigen is presented to agriculture. Antibody activity and CD8 + killer T cells highly regulated CD4 + T-cell helper subset. CD4 + T cells provide growth factors or signals these cells to proliferate and signal them to function more efficiently. This set of interleukins or cytokines that are produced and allocated CD4 + T cells, often crucial for the activation of natural killer cells, macrophages, CD8 + T cells, and PMNs are listed in the table below. Roitt I, J Brostoff and D. 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