Jewett A, Cavalcanti M, Bonavida B
Department of Microbiology and Immunology, UCLA School of Medicine, University of California, Los Angeles 90095-1747, USA.
J Immunol. 1997 Nov 15;159(10):4815-22.
The interaction of purified nonactivated human NK cells with target cells overnight results in functional anergy and apoptosis in NK cells and in a change of the NK phenotype from CD16+ CD56+ CD69- to CD16(dim/-) CD56(+/dim/-) CD69+. These studies suggested that signaling triggered by the FcR CD16 may be implicated in target cell-mediated anergy/apoptosis of NK cells. We hypothesized that triggering CD16 by anti-CD16 Ab should result in NK cells exhibiting functional and phenotypic properties similar to those obtained following triggering of NK cells with target cells. The findings demonstrate that the anti-CD16 mAb-treated NK cells acquired the CD16- CD56(+/dim) CD69+ Fas+ phenotype and lost their cytotoxic function, a significant number of the NK cells underwent apoptosis, and a selective induction of TNF-alpha synthesis and secretion was observed. The coaddition of IL-2 to anti-CD16 Ab-treated NK cells resulted in enhanced secretion of TNF-alpha and augmentation of the frequency of cell death. However, a minor subset of NK cells exhibited potent cytotoxic function and proliferated. The anti-CD16-induced effects in NK cells were largely abrogated by the addition of either anti-TNF-alpha Ab or TNF-binding protein in the cultures. There was an enhancement of NK cell killing following the addition of exogenous TNF-alpha into the culture. Cytochalasin B selectively triggered the secretion of TNF-alpha and significantly augmented the frequency of apoptosis of anti-CD16-treated NK cells. These findings demonstrate an important and pivotal role of endogenous TNF-alpha synthesis and secretion by NK cells in the induction of functional anergy and apoptosis in anti-CD16-treated NK cells.
纯化的未激活人自然杀伤（NK）细胞与靶细胞过夜相互作用，会导致NK细胞出现功能无反应性和凋亡，并使NK细胞表型从CD16+ CD56+ CD69-转变为CD16(dim/-) CD56(+/dim/-) CD69+。这些研究表明，由FcR CD16触发的信号可能与靶细胞介导的NK细胞无反应性/凋亡有关。我们推测，用抗CD16抗体触发CD16应会使NK细胞表现出与用靶细胞触发NK细胞后获得的功能和表型特性相似的特性。研究结果表明，经抗CD16单克隆抗体处理的NK细胞获得了CD16- CD56(+/dim) CD69+ Fas+表型并丧失了细胞毒性功能，大量NK细胞发生凋亡，且观察到肿瘤坏死因子-α（TNF-α）合成和分泌的选择性诱导。向经抗CD16抗体处理的NK细胞中共同添加白细胞介素-2（IL-2），会导致TNF-α分泌增加和细胞死亡频率升高。然而，一小部分NK细胞表现出强大的细胞毒性功能并增殖。在培养物中添加抗TNF-α抗体或TNF结合蛋白后，抗CD16诱导的NK细胞效应在很大程度上被消除。向培养物中添加外源性TNF-α后，NK细胞杀伤作用增强。细胞松弛素B选择性地触发TNF-α的分泌，并显著增加经抗CD16处理的NK细胞的凋亡频率。这些研究结果表明，NK细胞内源性TNF-α的合成和分泌在经抗CD16处理的NK细胞功能无反应性和凋亡的诱导中起重要且关键的作用。
