RADIOPROTECTIVE EFFECTS OF WR-2721, BRONCHO-VAXOM(R) AND THEIR COMBINATIONS - SURVIVAL, MYELOPOIETIC RESTORATION AND INDUCTION OF COLONY-STIMULATING ACTIVITY IN MICE

The possibilities of combined radioprotection, using preirradiation WR -2721 administration and post- or preirradiation Broncho-Vaxom(R) admi nistration in lethally whole-body gamma-irradiated mice were investiga ted. LD(50/30) dose reduction factors (DRFs) for mice treated with WR- 2721 (200 mg/kg i.p. 30 min before irradiation), Broncho-Vaxome(R) (25 mg/kg i.p. 24 h before irradiation), or both agents were 1.92, 1.17 a nd 2.07, respectively. These results demonstrated at least additive ra dioprotective effects of both agents, manifested in increased survival of irradiated mice. Radioprotection from 17 Cry was optimal when WR-2 721 in combination with Broncho-Vaxom(R) was given 30 min before irrad iation and Broncho-Vaxom(R) 24 h before or 4-8 h after irradiation. Co mbined modality treatments were also more effective than individual tr eatments alone in accelerating the bone marrow GM-CFC restoration. Dur ing the first days after irradiation enhanced colony-stimulating activ ity (CSA) of the lungs was observed in mice with postirradiation injec tion of Broncho-Vaxom alone or in mice injected with WR-2721 and Bronc ho-Vaxom(R) (8 h after irradiation), as well as in mice only irradiate d.