INDUCTION OF CYTOTOXIC T-CELL RESPONSES IN NEWBORN MICE BY DNA IMMUNIZATION

Cytotoxic T cells (CTL) play a critical role in controlling viral infe ctions. Infection of neonatal NFS/N mice with a high dose of Cas-Br-M murine leukemia virus, a neuropathogenic type C retrovirus, results in virus-induced neurologic disease and in their failure to generate a p rotective CTL response. Cas-Br-M-specific CTL are necessary in the pro tection of neonatal mice from Cas-Br-M-induced neurologic disease. Her e we demonstrate that intramuscular inoculation of newborn mice with n aked DNA expressing the full length Cas-Br-M genome induces a virus-sp ecific CTL-mediated response. This CTL response is mediated by CD8(+) T cells, is long lasting and when transferred to susceptible neonatal recipients, protects them from Cas-induced neurologic disease. We also provide evidence that the intramuscular inoculation of neonates with plasmid DNA encoding only env sequences induces a dose-dependent CTL r esponse in the absence of an anti-MuLV antibody response. (C) 1997 Els evier Science Ltd.