NUKLEONIKA 2005, 50(Supplement 2):S21-S24
Ewa M. Nowosielska, Jolanta Wrembel-Wargocka, Aneta Cheda, Emil Lisiak, Marek K. Janiak
Military Institute of Hygiene and Epidemiology,
Department of Radiobiology and Radiation Protection,
4 Kozielska Str., 01-163 Warsaw, Poland
Experimental evidence from the recent years indicates that low-level irradiations with X- or gamma rays
may inhibit development of both primary and secondary tumours and stimulate the activity of natural
anti-tumour immune mechanisms. Natural killer (NK) cells play an important role in anti-tumour defence
of the host. In the present investigation cytotoxic activity, production of interferon-g,
and expression of the Fas ligand (FasL) were estimated in the NK splenocytes collected from BALB/c mice
whose whole body was pre-exposed to irradiation with 0.1, 0.2, or 1.0 Gy X-rays. The results indicate
that cytotoxic activity of the irradiated NK cells was significantly stimulated compared to that of
the NK effectors obtained from the sham-exposed mice. This effect was totally abrogated by injection
of the anti-asialo GM1 antibody. In addition, compared to the control mice, NK cells obtained
from the irradiated animals exhibited reduced surface expression of FasL. Collectively, the obtained
results suggest that the inhibitory effect of the low-level irradiations with X-rays on the development
of pulmonary tumour nodules may be directly associated with stimulation by such exposures of
anti-neoplastic functions mediated by NK cells.