T cells (also called T lymphocytes) are one of the main components of the adaptive immune system. They are vital in hosting an immune response against pathogens.T cells play a major role in defence against intracellular pathogens such as viruses, protozoa and intracellular bacteria, and in immunity to extracellular pathogens by providing help for the antibody response.This article shall discuss the production of T cells, the different types present in the immune system and relevant clinical conditions.

Production of T Cells

T cells originate from haematopoietic stem cells which are produced in the bone marrow. These stem cells then split into 2 progenitor groups, myeloid and lymphoid progenitor cells, the latter of which then differentiate into T cells and B cells.

T cells then migrate to the thymus gland, in the anterior mediastinum, to undergo the process of maturation. They enter the cortex and proliferate, mature and pass onto the medulla of the thymus. From the medulla, mature T cells enter the circulation. These mature T cells are now capable of responding to antigens in the periphery.

The thymus shrinks as we age and so provides fewer T cells over time. As such, the older a person becomes, the more important T cell expansion in the periphery becomes in providing immune protection.

Manuscripts with relevance to the scope can be submitted to our Email: clin.immunores@eclinicalsci.com or Immunologyres@immunologyjournals.org or Online Submission Immunology