淋巴因子激活的NK细胞杀伤肿瘤细胞的免疫电镜观察

Immunoelectron microscopic stodies on the process of tumor cytolysis mediated by lymphokine activated NK cells

用胶体金标记的扫描与透射免疫电镜术观察ＣＤ１６￣＋淋巴因子激活的杀伤细胞（ＬＡＫ）杀伤肺腺癌细胞系ＬＴＥＰ＿（ａ２）或人红白血病细胞Ｋ５６２的过程。发现ＣＤ１６￣＋ＬＡＫ细胞能伸出分支的指状突起较深地插入肿瘤细胞胞浆内，造成靶细胞表面大小深浅不等的陷窝，及陷窝内局部细胞膜损伤。在ＣＤ１６￣＋ＬＡＫ细胞这种指状突起基底部附近的胞浆内，有大量胞浆颗粒与囊泡聚集。靶细胞被攻击后常发生凋落型死亡。同时可见坏死型死亡。说明ＣＤ１６￣＋ＬＡＫ细胞比自然杀伤（ＮＫ）细胞更具攻击力量，从而体现出更高的杀伤活性。本文结果对淋巴因子激活的ＮＫ细胞是ＬＡＫ的效应细胞提供了直接证明。

he second fraction(F2) cells isolated from PBL by discontinuous Percoll density gradient centrifugation were used as the enriched natural killer (NK)cells. After being incubated with rIL2,the ac-tivated F2 cells(F2 LAK)acquired the cytolytic ability upon NK resistant tumor cell lines. In F2 LAK.about 45% of the cells were CD16￣+, therefore F2 LAK were used as the enriched CD16￣+ LAK cells(or lymphokine activated NK cells)The cytolysis process of lung adenocarcinoma LTEPa- 2 or K562 tumor cells mediated by CD16￣+ LAK cells were investigated with colloidal gold labelled Ab via scanning and transmission immunoelectron microscopy. The results showed tMt the CD16￣+ LAK cells extended their protrusions deep into the target cells. Crypts of various diameter and depth were observed on the surface of the target cells with membrane injury at the bottom of the crypts.It was found that the cytoplasmic granules and vacuoles of CD16￣+ LAK cells were concentrated in the area close to the E- T conjugated side, and some-times the granules were found within the LAK protrusions.The attacked target cells died by apoptosis and necrosis.This study provided direct evidence that lymphokine activated NK cells are effectors of LAK cells.