IONIZING-RADIATION MODULATES THE SPREAD OF AN APATHOGENIC RABIES VIRUS IN MOUSE-BRAIN

Ionizing radiation has been shown to affect a broad range of viral dis eases including neurotropic infections through an immunosuppression me chanism. In the present study we have investigated the effect of ioniz ing radiation on the characteristics of neurotropic infection by rabie s virus, which has the unusual feature of infecting almost exclusively neurons. In order to analyze better the effect produced, the study co ncerned the spread of an apathogenic rabies virus variant in mouse bra in. Irradiation was shown to increase both the intensity and duration of the infection in a reversible and dose-dependent manner and was eff ective in whole-body irradiation and in head-protected body irradiatio n, whereas cephalic irradiation had no effect. These results underline the role played by the immune system in the regulation of neurotropic virus infections in the brain and show that phenomena such as viral c learance and timecourse of a neurotopic viral infection may be signifi cantly modified by ionizing radiation, even for viruses whose infectio n involves only neurons.