Vaccinia virus infection of the central nervous system in X-irradiated mice

The effect of X-irradiation on experimental vaccinia infection of BALB/c mice was studied. As compared with nonirradiated controls, the X-irradiated animals exhibited (i) a time lag in virus replication (delayed, but protracted replication); (ii) a delayed and repressed immune response: (iii) more severe acute cytocidal infection of leptomeninges, choroid plexus, ependyma, and vessels, with extensive damage to the brain-barrier system; and (iv) noncytocidal, latent infection of glial cells and neurons. Several animals developed acute or subacute demyelination disease, resembling experimental allergic encephalomyelitis or postinfectious encephalomyelitis.