Lymphocytes are one of the five kinds of white blood cells or leukocytes, circulating in the blood. Although mature lymphocytes all look pretty much alike, they are extraordinarily diverse in their functions. The most abundant lymphocytes are: B-Lymphocytes (often simply called B-Cells) and T-Lymphocytes (likewise called T-Cells). T-Cells are produced in bone marrow. The precursors of T-Cells leave the bone marrow and mature in the thymus. T-Cells recognize antigen through a cell surface receptor known as the TCR (T-Cell Receptor), which has a structural and functional similarilities to the membrane-bound Immunoglobulin that serve as the BCR (B-Cell Receptor) for antigen. TCRs are heterodimeric glycoproteins in which each polypeptide chain consist of a variable domain and a constant domain, similar to [...]