Effect of irradiation on hepatic natural killer cells

✍ Scribed by Karin Vanderkerken; Luc Bouwens; Peter Kuppen; Wilfried De Neve; Kit Van Den Berg; Marijke Baekeland; Eddie Wisse

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 689 KB
• Volume: 19
• Category: Article
• ISSN: 0270-9139
• DOI: 10.1002/hep.1840190621

✦ Synopsis

The rat liver contains a population of natural killer cells consisting of two morphologically and functionally different eubsets, a low-density and a highdensity fraction. In this work we describe the influence of low-doee radiation on hepatic natural killer activity. The effect on the cytotaxicity against YAC-1 lymphoma and CC531 colon adenocarcinoma tumor cells was measured in chromium-61 assays, and morphological changes were analyzed by means of electron mi-c~y)~copy. The low-density natural killer fraction showed increased cytotoxicity against YAC-1 which was associated with an increased binding of natural killer cells to the YAC-1 tumor cells shortly after irradiation. These phenomena were paralleled by an increased number of multivesicular bodies and cytoplasmic granules with an electron-lucent halo. In contraat, the other hepatic natural killer cell fraction, the high-density natural killer cells, did not show i n c r e d cytotdcity, binding or morphological alterations. The radiation-etimulated lysis of YAC-1 cells was ale0 observed when in uiuo irradiated cells were isolated and tested immediately for in uitro lysis of YAC-1 cells. Sixteen hours after in uitro or in v i m irradiation, the cytotoxicity of hepatic natural killer cells against YAC-1 was no longer enhanced. The cytolyeis of and binding of hepatic natural killer cells to CCS31 colon adenocarcinoma cells was not stimulated by in u i f m irradiation. From these experiments, we conclude that low-dose radiation stimulates the cytotanicity of hepatic low-density natural killer cells against YAC-1 lymphoma cells immediately after irradiation as the reault of enhanced binding of the cells to the tumor cells, in addition to the synthesis of new cytotoxic granules.