Overview
T cell, also called T lymphocyte, type of leukocyte (white blood cell) that is an essential part of the immune system. T cells are one of two primary types of lymphocytes—B cells being the second type—that determine the specificity of immune response to antigens (foreign substances) in the body.T cells originate in the bone marrow and mature in the thymus. In the thymus, T cells multiply and differentiate into helper, regulatory, or cytotoxic T cells or become memory T cells. They are then sent to peripheral tissues or circulate in the blood or lymphatic system. Once stimulated by the appropriate antigen, helper T cells secrete chemical messengers called cytokines, which stimulate the differentiation of B cells into plasma cells (antibody-producing cells). Regulatory T cells act to control immune reactions, hence their name. Cytotoxic T cells, which are activated by various cytokines, bind to and kill infected cells and cancer cells.Because the body contains millions of T and B cells, many of which carry unique receptors, it can respond to virtually any antigen.
Types of T-Cells
Naive T cells are are cells that have not yet encountered their specific antigen. In peripheral lymphoid organs naïve T cells can interact with antigen presenting cells (APCs), which use an MHC molecule to present antigen. If the T cell recognises a specific antigen, it will proliferate and differentiate into effector T cells of a particular type. Effector T cells will interact with host cells (rather than the pathogen) to carry out their immune function.The cell either uses a co-receptor called CD8 or CD4 to bind to the MHC molecule – these proteins help us to differentiate major groups of effector T cells. Naïve T cells with CD8 will become cytotoxic T cells and those with CD4 will become T helper cells, each of which are specialised in particular tasks.
Cytotoxic T Cells (CD8 T Cells) Cytotoxic T cells kill their target cells, primarily by releasing cytotoxic granules into the cell to be killed. These cells recognise their specific antigen (such as fragments of viruses) when presented by MHC Class I molecules that are present on the surface of all nucleated cells.
T-Helper Cells (Th) (CD4 T Cells) T helper cells have a wider range of effector functions than CD8 T cells and can differentiate into many different subtypes, such as Th1, Th2, Th17 and regulatory T cells.
Immunity Tests
Immunoglobulins blood test measures the amount of immunoglobulins, also known as antibodies, in your blood. Antibodies are proteins made by the immune system to fight disease-causing substances, like viruses and bacteria. Your body makes different types of immunoglobulins to fight different types of these substances.An immunoglobulins test usually measures three specific types of immunoglobulins. They are called igG, igM, and IgA. If your levels of igG, igM, or IgA are too low or too high, it may be a sign of a serious health problem.Influenza A and B Antigen, Immunoassay - Influenza is an acute viral disease that is seasonal in incidence, occurring in the colder months. The illness classically presents with sudden onset of fever, chills, headache, myalgia and a non-productive cough. Influenza A or B virus cause the majority of clinically significant disease, with influenza C virus being responsible only for mild, predominately upper respiratory tract illness. Patients who present with suspected influenza may benefit from treatment with antiviral agents. Since the therapeutic options have expanded to include options for the treatment of influenza B disease, it is important to rapidly distinguish influenza A from influenza B in order to allow physicians a choice in selective antiviral intervention. This will also allow for the appropriate preventative intervention to be taken in institutions where measures can be taken for susceptible individuals. It is therefore important to not only rapidly determine whether influenza is present, but also which type of influenza virus is present.Looking for a drug test laboratory near me?. Tuhealthy App helps you to find female hormone blood tests.
