A HIGHLY ATTENUATED HOST RANGE-RESTRICTED VACCINIA VIRUS-STRAIN, NYVAC, ENCODING THE PRM, E, AND NS1 GENES OF JAPANESE ENCEPHALITIS-VIRUS PREVENTS JEV VIREMIA IN SWINE

A highly attenuated strain of vaccinia virus (NYVAC) was engineered to express the Japanese encephalitis virus (JEV) prM, E, and NS1 genes or the prM and E genes. The recombinant viruses were tested as vaccine candidates in pigs, a natural host of JEV. JEV-neutralizing and hemagglutination-inhibiting antibodies appeared in swine sera 7 days after immunization with 108 PFU of the recombinant viruses and increased after a second dose at 28 days. The JEV levels detected in the serum after JEV challenge (d56) of the swine with 2 × 108 PFU of JEV were significantly reduced in animals inoculated with the recombinant viruses. These results demonstrate the ability of these NYVAC-vectored recombinants to protect pigs from JEV viremia. © 1992.