T lymphocytes (or T cells) are a type of white blood cell belonging to the lymphocyte lineage, which plays an important role in the body's immune response. T lymphocytes originate from bone marrow hematopoietic stem cells and mature in the thymus. This article will discuss the development of T lymphocytes in the thymus and the classification of T lymphocytes.

Helper T cells were discovered in 1966 by a group of scientists at the University of Colorado in the United States. Helper T cells (or CD4+ T cells) are lymphoid cells originating from the bone marrow, differentiated and matured in the thymus. After maturity, they will migrate to peripheral tissues, lymph nodes or circulate in the peripheral blood.

The concept of immunosurveillance was introduced in 1957, describing the process by which the immune system performs the task of screening, detecting and destroying harmful agents such as bacteria, viruses, foreign cells or abnormal cells that have the ability to transform and develop into cancer cells.

T cells (or T lymphocytes) play an extremely important role in the human body's immune response system. This type of cell is developed from bone marrow hematopoietic stem cells, which then mature in the thymus. The process to activate T cells will go through different stages as well as different pathways. So how are T cells activated?