Also called T-cells. These are specialised cells which respond to stimulation by dendritic cells plus a peptide antigen. They have multiple roles in the immune response including directly attacking abnormal cells and regulating the response of other T cells.
Lymphoid cells concerned with cell-mediated immunity. They originate from lymphoid stem cells that migrate from the bone marrow to the thymus and differentiate under the influence of the thymic hormones. Various subpopulations have been described.
The T-lymphocytes are differentiated in the thymus, a small organ behind the sternum. The T-lymphocytes carry a protein complex on their cell surface that can recognise and bind antigens. The protein complex only reacts with the antigen specific to it, like to a key that only fits a specific lock. This results in activation of the T-lymphocytes. A distinction is made between cytotoxic T-lymphocytes that can bind and dissolve cells recognised as foreign, i.e. antigen-bearing cells, and the T-helper lymphocytes. By means of the production of various growth factors, these enable the differentiation between B-lymphocytes and cells producing antibodies.