T cell was also known as T lymphocytes, is a type of leukocyte that plays a central Part in cell-mediated immunity, it is called as T-cells because they mature in the thymus from thymocytes, most majority of human T cells Reposition their alpha and beta chains on the cell receptor and are designate alpha, beta T cells and are fragment of the adaptive immune system. Specialized gamma delta T cells, have invariant T-cell receptors with limited diversity, which can effectively available antigens to other T cells and are considered to be lump of the innate immune system.