Immune system stimulation - reduces cancer

[Jim Muckerheide <jmuckerheide@delphi.com>]

Group,

Two inquires indicate a problem linking to PubMed library abstracts.

The two abstracts provided were:
>>>
1. Radiat Res 1996 Nov;146(5):582-5
 Decreased incidence of thymic lymphoma in AKR mice as a result of chronic,
fractionated low-dose total-body X irradiation. 

 Ishii K, Hosoi Y, Yamada S, Ono T, Sakamoto K 
 Department of Radiology, Tohoku University School of Medicine, Sendai, Japan.

ABSTRACT (para breaks added :-)
  We have investigated whether low-dose total-body X irradiation could
suppress the development of lymphoma in AKR mice. 
Male mice were irradiated with 5 cGy three times a week or 15 cGy two times a
week from 11 weeks of age for 40 weeks. The incidences of lymphoma were 80.5%
in sham-irradiated mice, 67.5% in mice irradiated with 5 cGy three times a
week and 48.6% in mice irradiated with 15 cGy twice a week. 

  Incidence of lymphoma was significantly reduced by irradiation with 15 cGy
twice a week (P = 0.006). 

  The mean survival time was significantly prolonged from 283 +/- 3 days in
control mice to 316 +/- 10 days in mice irradiated with 15 cGy twice a week (P
= 0.008) and to 309 +/- 14 days in mice irradiated with 5 cGy three times a
week (P = 0.040). 

  Because about 80% of male AKR mice die of lymphoma, it is likely that the
prolonged life span observed in the irradiated mice is due to the reduced
incidence of lymphoma.
>>>

>>>
2. Physiol Chem Phys Med NMR 1995;27(1):17-23
 Enhanced mitogen-induced proliferation of rat splenocytes by low-dose
whole-body X-irradiation. 

 Ishii K, Yamaoka K, Hosoi Y, Ono T, Sakamoto K 
 Radiation Safety Group, Central Research Institute of Electric Power
Industry, Tokyo, Japan.

ABSTRACT (para breaks added :-)
  To elucidate the stimulative effect on the immune system, we studied the
effect of acute low-dose whole-body X-irradiation on the mitogen-induced
proliferative responses of rat splenocytes and thymocytes. 

  Concanavalin A (Con A)-induced mitogen response of rat splenocytes 4 hours
after 5 cGy irradiation was significantly higher (by 80%, p < 0.02) than that
in sham-irradiated controls; whereas that of rat thymocytes did not show
change after irradiation of 1-10 cGy. In the rats X-irradiated with doses
greater than 25 cGy, Con A-induced mitogen responses of splenocytes and
thymocytes were reduced. 

  In a way similar to the Con A-induced mitogen response of splenocytes, the
mitogen response of splenocytes induced by phytohemagglutinin (PHA) or
lipopolysaccharide (LPS) was significantly increased by X-irradiation with 5
cGy (by 50%, p < 0.02). The enhancement of mitogen response of splenocytes was
observed within a few hours after irradiation, being a temporary effect. 

  After 5 cGy irradiation the level of leukotriene B4 (LTB4) in the
supernatant fraction of the splenocyte suspension showed a significant
increase (by 40%, p < 0.05).
>>>

[Note: During "temporary effects" from acute doses, the enhanced immune
competence reduces latent damage (e.g., removing pre-cancerous cells) with
long-term health benefits. It takes the organism some time without such a
stimulatory effect to return to an equivalent level of damaged cells - kind of
like when I clean the house! :-)  Some of the other beneficial effects studied
last up to 2 months.]

(Thought you might also be interested in a paper from Ishii's his earlier
work:

>>>
3. Nippon Igaku Hoshasen Gakkai Zasshi 1990 Oct 25;50(10):1262-7

 [Augmentation in mitogen-induced proliferation of rat splenocytes by low dose
whole body X-irradiation]. 
 [Article in Japanese]

 Ishii K, Muto N, Yamamoto I 
 Department of Immunochemistry, Faculty of Pharmaceutical Sciences, Okayama
University.

 The hypothesis of radiation hormesis has been proposed. To elucidate the
hormetic effect on the immune system, we studied the effect of low dose whole
body irradiation on the in vitro mitogen-induced proliferation of rat
thymocytes and splenocytes. 

  The rats were irradiated with low doses (0.01-2 Gy) of X-ray and the cells
were cultivated in the presence of various mitogens. The cell proliferation
was evaluated by the incorporation of 3H-thymidine into the cells.
Concanavalin A (Con A)-induced proliferation of splenocytes prepared at 4 hr
after irradiation was augmented with 0.05 Gy, whereas that of thymocytes was
not affected. 

  Irradiation of rats with 0.05 Gy also induced the enhanced proliferation of
splenocytes stimulated by phytohemagglutinin or lipopolysaccharide, though
their responses were lower than that by Con A. This augmentation in
mitogen-induced proliferation of splenocytes was observed within a few hours
after irradiation, being a temporary effect. 

  These results suggest that very low dose whole body irradiation possibly
induce a hormesis-like effect on the immune splenocytes.
>>>
Regards, Jim
muckerheide@mediaone.net
Radiation, Science, and Health
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