What is true about T-lymphocytes in mammals?

T cells account for about (80 \%) of all lymphocytes. They are named T cells because they mature in the thymus, a gland found in the chest. There are three types of T cell lymphocytes: - Cytotoxic T cell - Suppressor T cell - Helper T cell Helper T cells are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses. They not only help activate $B$ cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic $T$ cells to kill infected target cells. A cytotoxic T cell is a Tlymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected (particularly with viruses), or cells that are damaged in other ways. The regulatory T cells formerly known as suppressor T cells are a subpopulation of T cells that modulate the immune system, maintain tolerance to self-antigens, and prevent autoimmune disease. So, the correct answer is 'There are three main types-cytotoxic T-cells, helper T-cells, and suppressor T-cells'.