新生儿脐血淋巴细胞IL-2R的表达

白细胞介素2(IL-2)及其受体(IL-2R)系统在免疫调节中发挥着重要的作用。本研究采用间接免疫荧光技术检测了新生儿脐血淋巴细胞IL-2R表达情况及其T细胞亚类水平。结果表明健康足月新生儿脐血Tac阳性细胞百分率明显低于正常成人,且异常新生儿的减低更为明显;而健康足月新生儿脐血CD_4阳性细胞和CD_4 CD_8比值却明显高于正常成人。说明尽管新生儿具有足够数量的T细胞(CD_3阳性细胞)和辅助性T细胞(CD_4阳性细胞),且CD_4/CD_3比值还高于成人,但其活化淋巴细胞上IL-2R的表达不足,故影响IL-2作用的发挥;加之新生儿细胞表面CD抗原标志与自身功能发育的非同步性,导致其细胞免疫功能低下。

EXPRESSION OF INTERLEUKIN-2 RECEPTOR ON LYMPHOCYTE OF CORD BLOOD IN NEONATES

Interlukin-2 (IL-2) and Interlukin-2 receptor (IL-2R) play an important role in immune regulation. With indirect immunoflurorescent technique, we assessed the expression of IL-2R on activated lymphocytes as well as the ratios of T-cell subsets in blood samples from neonates and adults.The percentage of Tac positive cell in cord blood of newborn was significantly higher than that in blood of normal adult. However, the percentage of CD4 positive cells and the ratio of CD4/CD3 is obviously higher in blood of neonates. These results indicate that although the number of T cell (CD3+ cell) and Th cell (CD; cell) is adequate and the ratio CD4/CD3 is higher in newborn, the expression of IL-2R on activated lymphocytes is not sufficient. This results in suppressed biologic activity of IL-2. Moreover, CD antigen marker on lymphocytes does not necessary bear the corresponding level of immune function in the newborn. These factors combined lead to the decreased cell-mediated immune function observed.