以往的免疫观念认为，机体对抵抗外来病原微生物发挥的防御作用，即是免除传染病的自身能力。近年发现，机体的免疫系统还具有监视和杀灭体内出现的癌变细胞，清除体内衰老死亡细胞的功能，也即是“免疫监视”和“免疫自稳”作用。人们发现，衰老是由于人体免疫力逐渐降低导致 In the past, the immunization concept held that the body’s defensive effect against foreign pathogenic microorganisms is the ability to eliminate infectious diseases. In recent years, it has been found that the body’s immune system also has the function of monitoring and killing cancerous cells in vivo and clearing dead cells in the body, namely, “immune surveillance” and “immune self-stabilization”. People find that aging is caused by the gradual decrease of human immunity