Protective effect of measles virus inoculation on subacute sclerosing panencephalitis virus-infected mice.

The Biken strain of subacute sclerosing panencephalitis (SSPE) virus caused a fatal neurologic disease in adult mice after intracerebral inoculation. However, the mice were completely protected from the disease when a high dose of measles virus was given intracerebrally after the SSPE virus infection. The measles virus inoculation induced interferon production and immune responses. An experiment with athymic nude mice showed that interferon and anti-measles antibody were able to prolong the incubation period of the disease but not to protect the SSPE virus-infected nude mice from death. For complete protection, T lymphocytes appeared to be essential. The present study suggested that the protective effect of measles virus inoculation is basically due to the induction of immune responses and that SSPE virus infection in mice is susceptible to immune reactions.