Dr. Chu often uses a vivid analogy to explain this phenomenon: "Everyone has some resistance capacity; when an unknown object enters the system, the immune system is alerted and rejects and destroys the object.
朱樹勳常用一個很生動的譬喻解釋這個現象：「每個人都有免疫力（抵抗力），當體內有異物入侵時，免疫系統就會警覺、排斥並摧毀入侵物，其功能恰似國家的安全系統。