The lifespans of blood cells is relatively short but the numbers remain constant through replenishment. This means that there is a rate at which blood cells are formed. If the number of cells is reduced then an infection could follow and the rate of production would be increased. Consequently, it will be induced to differentiate into the erythroid cell line and eventually for mature erythoid cell line and become an erythrocyte. At least two lymphocyte-inducing microenvironment exist.
Lymphocytes have a unique structure which allows then to respond to antigens.
There are two major classes of lymphocytes which are designated as T cells and B cells. The T and B cells are indistinguishable by conventional light microscopy. Each is almost entirely filled by the nucleus. The T and B cell can be distinguished from one another by membrane markers. Classification of lymphocytes on the basis of surface markers make use of two important classes of characteristics.