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Define T Cells

T cells are a category of leukocytes( also known as white blood cells) is an essential part of the immune system. T cell is one of the two primary types of lymphocytes and B cells is the second type, which determines the specificity of the immune response to the foreign bodies in the body.  It is born in the hematopoietic stem cells and found in the bone marrow. T cells' name is derived from the organ where they have developed. After the migration of these cells to the thymus, the precursor cells divide into several different types of T cells.  

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T Cell is What Type of Cell?

T cells are one of the three main types of lymphocytes. Other types are B Cells and natural killer cells. T cell lymphocytes are different from B cells and natural killer cells, in T cells they have a protein called a T cell receptor which populates their cell membrane. These receptors are capable of recognizing various types of specific antigens, these are the substances that provoke an immune response. T cells do not utilize antibodies to fight germs as in B cells. 

Types of T cells 

T cells are grouped into a series of subsets based on their function, initially, it is divided into two types: conventional adaptive T cells and innate-like T cells.

Conventional adaptive T cells have - 

  • Helper T cells - It releases molecules like cytokines into the bloodstream to warm the immune system, when there is the presence of dangerous cells or viruses. 

  • Cytotoxic T cells - These cells attach themselves to other cells in the body. If the cytotoxic T cells come to know that a cell is diseased or pathogenic, it will do one of two things. It will force the cell to commit suicide or secrete an enzyme that will kill the cell. 

  • Memory T cells - It is an antigen-specific T cell, which remains long term after an infection has been eliminated. These cells are quickly converted into a large number of effector T cells on reexposure to the specific invading antigen, which provides a rapid response to the past infection. 

  • Regulatory T cells - It helps to maintain immunological tolerance. The major role of this cell is to shut down T cells mediated immunity towards and end of the immune reaction.

Category of T Cells in Innate Like are -

  • Natural killer T cells - It is the heterogeneous group of T cells, having the property of both T cells and the natural killer cells. 

  • Mucosa-associated invariant T cells - These are unique innate-like T cells, which bridges innate and adaptive immunity.

  • Gamma delta T cells - They have the distinctive T cell receptor on their surface and even it is believed to have a prominent role in the recognition of lipid antigens.

What is the Function of T cells?

Some of the important function of the T cells are 

  • T cells are a type of lymphocyte immune cells that protects the body from pathogens and also from cancer-causing cells.

  • T cells originate in the bone marrow and it gets mature in the thymus. It is very important for cell-mediated immunity and the activation of immune cells to fight infection.

  • Cytotoxic T cells actively destroy the infected cells with the use of granule sacs that contain digestive enzymes.

  • Helper T cells activate cytotoxic T cells, macrophages, and stimulate antibody production by B cell lymphocytes.

  • Regulatory T cells suppress the actions of B cells and T cells to decrease the immune response when there is no need for a highly active response.

  • Natural Killer T cells identify the infected and the cancerous cells from normal body cells and attack those cells that do not contain molecular markers.

  • Memory T cells protect against the previously encountered antigens and it may provide lifetime protection from some of the pathogens.

Difference T Cells vs White Blood Cells 

After going through define T cells and function, It would be easy to say that there is no difference in T cells vs white blood cells. The T cell is part of the white blood cells. Both of them help to protect the body from foreign invasion and infection, performing their respective functions as described above, in what is the function of T cells?

Did You Know?

Where do T cells come from? Most of the T cells are made when you are young. So the kids have bigger thymus compared to the adults. It is also the period when T cells get examined to get rid of any that would attack the healthy cells in your body. 

FAQ (Frequently Asked Questions)

1. What is the Role of the T Cells?

Answer. T cells are one of the major components of the adaptive immune system. The role of T cells includes indirectly killing infected host cells, activating other immune cells, producing cytokines and regulating the immune system.  

2. How Do T Cells Kill Cells?

Answer. When a perfectly shaped virus antigen on an infected cell fits into the Killer T-cell receptor. The T cells secrete perforin and cytotoxins. Cytotoxins go directly inside the cell through the pore, destroying it and any other viruses inside, So Killer T-cells are also known as Cytotoxic T-cells.

3. Are T Cells White Blood Cells?

Answer. Yes, T cells are white blood cells also known as lymphocytes. The main function of these cells is to prevent and fight against the disease. There are two types T cells, one is T cell and the other is B cells.