A T cell, also known as a T lymphocyte, is a type of white blood cell that plays a key role in the immune system's response to foreign substances in the body. T cells are a vital component of the adaptive immune system, which is responsible for recognizing, destroying, and remembering specific pathogens or abnormal cells.
T cells develop in the bone marrow, but they mature in the thymus gland, which is where they obtain their name. They are distinguished from other types of lymphocytes, such as B cells, by the presence of a T cell receptor (TCR) on their surface. The TCR allows T cells to identify antigens, which are proteins or foreign substances that trigger an immune response.
There are several types of T cells, including helper T cells (CD4+), cytotoxic T cells (CD8+), regulatory T cells (Tregs), and memory T cells. Helper T cells assist other immune cells in their functions, cytotoxic T cells directly attack infected or abnormal cells, regulatory T cells modulate the immune response to prevent overreaction, and memory T cells remember and respond more effectively upon subsequent exposure to the same antigen.
T cells are able to recognize antigens from infected cells or abnormal cells, bind to them through their TCR, and initiate an immune response. They can secrete proteins known as cytokines, which coordinate the actions of other immune cells, leading to the destruction of the targeted cells or pathogens.
Overall, T cells are crucial for the proper functioning of the immune system, ensuring the eradication of harmful substances, pathogens, and abnormal cells, and contributing to the body's defense against diseases.
