It is through the actions of this system including the spleen, the thymus, lymph nodes and lymph ducts that our body is able to fight infection and to ward off invasion from foreign invaders.

• 人体的自身免疫系统可以对抗疾病和外界病毒的入侵，而免疫系统主要就是由脾、胸腺、淋巴结、淋巴管组成的。