Lymphocete
There are two kinds of lymphocytes, the B and the T-lymphocytes. In the adult, both types of lymphocytes ate derived from common stem cells in the bone-marrow. In the foetus they are also formed in the yolk-sac, the firer and also possibly the thymus. The T-lymphocytes (or thymus-dependent lymphocytes) migrate to the thymus, where they come under the influence of the hormone thymosin and become immunologically competent.
