CD4单克隆抗体在体内诱导小鼠胸腺细胞凋亡

为研究抗ＣＤ４ ＭｃＡｂ引起胸腺细胞减少的机理，本课题探讨了ＣＤ４ ＭｃＡｂ诱导胸腺细胞发生凋亡的可能性。小鼠注射抗ＣＤ４ ＭｃＡｂ后，皮质胸腺细胞体积缩小，染色质凝聚；ＰＩ染色后经流式细胞计测定，显示大量的亚二倍体细胞（凋亡细胞，Ａｐｏｐｔｏｔｉｃ ｃｅｌｌｓ），与正常小鼠相比Ｐ〈０．００１；片断化ＤＮＡ的百分比也明显高于正常小鼠，Ｐ〈０．０１。片断化ＤＮＡ在凝胶电泳上呈现典型的阶梯现象。细胞内

APOPTOSIS(PCD) OF MURINE THYMOCYTES INDUCED BY ANTI-CD4 McAb IN VIVO

In previous experiments,we found that anti-CD4 McAb administration led to depletion of thymocytes in mice. Here ,we explored the possibility that anti-CD4 McAb could induce apoptosis of thymocytes. It has been shown that cortical thymocytes underwent apoptosis as characterized by morphologic changes with chromatin condensation and DNA fragmentation after anti-CD4 injection in mice. A flow cytometric method for measuring the percentatge of apop-totic nuclei(hypodiploid DNA) after PI staining,and colorimetric methods measure DNA fragmentation in the nuclear extracts, both of them were much higher in anti-CD4 group than thymocytes of normal mice. (P<0. 01 and P< 0. 001). Anti-CD4 induced apoptosis was inhibited by cycloheximide or IL-2. The ladder pattern of DNA fragments, characteristic of apoptosis ,appeared in anti-CD4 group. All results indicated that the anti-CD4 McAb could accelerate apoptosis of thymocytes,therefore the number of thymocytes was decreased.