AVIPOX VIRUS-VECTORED JAPANESE ENCEPHALITIS-VIRUS VACCINES - USE AS VACCINE CANDIDATES IN COMBINATION WITH PURIFIED SUBUNIT IMMUNOGENS

An avipox virus, canarypox (ALVAC), which is naturally host-range rest ricted, was used to construct recombinants encoding the Japanese encep halitis virus (JEV) prM, E and NS1 genes (vCP107) and prM and E genes (vCP140). Mice immunized with these recombinant viruses produced JEV n eutralizing antibodies and were protected from lethal JEV challenge. P rotection was also observed in mice immunized with a subunit vaccine c andidate, consisting of extracellular particles (EPs; RNA-free subvira l membrane vesicles containing prM/M and E proteins) derived from HeLa cell cultures infected with a JEV-vaccinia recombinant. Mice primed w ith vCP107 and boosted with EPs had higher antibody levels than mice i mmunized twice with EPs alone, although the levels were comparable to that obtained in mice immunized twice with the recombinant virus. Mice immunized with a mixture of recombinant virus (vCP107) plus EPs had n eutralizing antibody titres higher than mice immunized with the recomb inant virus or EPs alone.