T-LYMPHOCYTES
T-lymphocytes are the class of lymphocytes, which are produced in the thymus (T means "coming from the thymus"). Some of these lymphocytes die in the thymus, others migrate into peripherical lymphoid tissues and become T-cells. They become morphologically distinguishable from B-lymphocytes only after stimulating by an antigen. Non-stimulated T- and B-cells are small cells (only a little larger than an erythrocyte), in which the nuclei occupy the most part of their volume. Both of them are activated by an antigen, which caises their proliferation and differentiation. There is little rough endoplasmic reticulum in activated T-cells, but, on the other hand, many free ribosomes.
This class of lymphocytes is responsible for the cell-mediated immune repsonse.