It is suggested that there are common antigenic determinants and similar structurebetween IL-2 and endogenous opioid peptides (EOP). This implies that the analgesic effect of IL-2 might be mediated by interaction between IL-2 and opioid receptors in CNS.

• 加之内源性阿片肽与IL－2分子有着共同的抗原决定基和结构相似性，提示IL－2可以与阿片受体直接结合产生中枢镇痛效应。