Effects of sizofiran on murine NK and LAK precurs or cell activity suppressed by X-irradiation

We examined the in vivo effects of sizofiran (SPG) on the suppressed anti-tumor effector cell activities after whole-body X-irradiation (3 Gy) in C57BL/6 mice. Total spleen cell number and the natural killer (NK) and lymphokine activated killer (LAK) precursor cell activities were significantly suppressed day 1 to 3 after X-irradiation. The reduced cell number, NK activity and LAK precursor cell activity eventually recovered and reached normal levels on day 5 to 7. We next examined the effects of SPG on the suppressed cellular activities. Single intramuscular (im) administration of SPG (500 μg/mouse), 3 days before or 1 or 2 days after X-irradiation significantly increased the reduced NK activity on day 3 after X-irradiation. The reduced LAK precursor cell activity 3 days after X-irradiation was significantly increased only when SPG was administered one day after the X-irradiation. These results indicate that treatment with SPG restores effector cell activity decreased by X-irradiation. (author)