Major roles of thymus gland in humans is/are

Thymus gland is a lobular gland present on dorsal side of heart. It is associated with the development of immune system. It contains lymphoid tissue that plays an important role in proliferation and maturation of T-lymphocytes. It secretes thymosin hormone which plays an important role in the differentiation of T-lymphocytes which are associated with cell mediated immunity. Thymosin also promotes formation of antibodies for humoral immunity. It also controls resistance to infection and formation of lymphocytes. Thymus gland degenerates with age resulting in decreased production of thymosin. That's why older people have weak immunity.