Occupational levels of radiation exposure induce surface expression of interleukin-2 receptors in stimulated human peripheral blood lymphocytes

Abstract

Interleukin-2 (IL-2) is a cytokine responsible for a variety of immune and non-immune stimulatory and regulatory functions, including the activation and stimulation of cytotoxic cells able to recognize and kill human tumour cells and T-cell proliferation and differentiation. We show that low doses of radiation, in the range commonly received by atomic radiation workers or as a result of minor medical diagnostic procedures (0.25 to 10 mGy), stimulate the expression of IL-2 receptors (IL-2R) on the surface of peripheral blood lymphocytes (PBL) taken from normal human donors. This stimulated surface expression after in vitro irradiation is an indirect effect, resulting from the secretion into the medium of a soluble factor from the irradiated cells. This factor can also stimulate IL-2R surface expression in unirradiated cells. Consequently, radiation stimulation of IL-2R expression in a large population of PBL shows a triggered-type response rather than being proportional to dose. These results demonstrate that normal human cells can respond to doses of radiation in the range of common occupational or medical exposures. The data also demonstrate a possible defence mechanism against environmental stress by which a radiation-exposed cell can use an indirect signalling mechanism to communicate with and influence the biological processes in an unexposed cell.

Induction of interleukin‐1β and interleukin‐6 mRNA by low doses of ionizing radiation in macrophages

“…The effects of low-dose irradiation on them should be examined, to investigate the mechanisms of augmented immune responses by low-dose irradiation. Furthermore, expression of IL-2 receptors, Eselectin, and intercellular adhesion molecule-1 has been reported to be induced by low-dose irradiation [24][25][26][27]. These effects might also be involved in the augmentation of immune responses.…”

The Bystander Effect: Recent Developments and Implications for Understanding the Dose Response

“…If two independent types of bystander effects exist, one damaging and another protective, then it should be possible to show that the protective system Xu et al (1996). Xu et al (1996). can reduce the effects of the damaging system.…”

“…Xu et al (1996). can reduce the effects of the damaging system. Using doses where bystander effects have been shown to occur, such experiments have been reported by Iyer and Lehnert (2002a).…”

Radiation-induced cancer: a modern view

“…Xu et al [34] showed that low doses of radiation, in the range commonly received as a result of medical diagnostic procedures (0.25-10 mGy), stimulate the expression of interleukin 2 (IL-2) receptors on the surface of peripheral blood lymphocytes taken from normal human donors. They irradiated human lymphocytes with a dose of 10 mGy, and calculated the percentage of IL-2 surface receptors 24 h later.…”

“…Xu et al [34] concluded that their ''data demonstrate a possible defence mechanism against environmental stress by which a radiation-exposed cell can use an indirect signalling mechanism to communicate with and influence the biological processes in an unexposed cell. '' This suggests that there almost certainly are bystander effects in operation involving intercellular signalling in vitro; what cannot be concluded, however, is that these bystander effects predominate over the essential stochastic ''one-track action'' caused by a single electron track in vivo, and therefore that they would modulate the LNT curve to any significant degree.…”