Effect of continuous irradiation with a very low dose of gamma rays on life span and the immune system in SJL mice prone to B-cell lymphoma.
Ionizing radiation has been shown to have dose- and dose-rate-dependent carcinogenic effects on the hematopoietic and lymphoreticular systems. We report here that continuous exposure to a low dose of gamma rays influences the course of spontaneous B-cell lymphoma in SJL mice. We studied the biological effects of 10 cGy year(-1) gamma rays on the life span of 560 4-week-old SJL/J female mice and on various parameters of the cell-mediated immune response. Life span was slightly prolonged. The mean survival was 397 days for controls and 417 days for irradiated mice that died with lymphoma (P = 0.34). In lymph nodes and spleen, lower percentages of CD4+ and CD8+ T cells were observed in irradiated mice before 32 weeks. Interestingly, the percentages of CD49+ NK cells were increased in the spleens of irradiated mice at 28 weeks (0.61 +/- 0.08% compared to 0.43 +/- 0.12% in controls, P = 0.01) and at 32 weeks (0.62 +/- 0.24% compared to 0.33 +/- 0.09%, P = 0.02), while NK cell activity remained unchanged in exposed mice. These results provide further support for the absence of harmful effects of a continuous very low dose of radiation on life span and incidence of lymphoma in SJL mice.
Lacoste-Collin
L
L
Laboratoire d'Histologie-Embryologie, Faculté de Médecine Rangueil, F-31062 Toulouse cedex, France. collin@cict.fr
Jozan
S
S
Cances-Lauwers
V
V
Pipy
B
B
Gasset
G
G
Caratero
C
C
Courtade-Saïdi
M
M
D000818:Animals; D001835:Body Weight / Q000528:radiation effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D003601:Cytotoxicity Tests, Immunologic; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005720:Gamma Rays; D007107:Immune System / Q000276:immunology* / Q000528:radiation effects*; D007694:Killer Cells, Natural / Q000528:radiation effects; D016393:Lymphoma, B-Cell / Q000276:immunology* / Q000532:radiotherapy; D051379:Mice; D015996:Survival Rate; D013997:Time Factors