Protection against lethal Japanese encephalitis virus infection of mice byimmunization with the highly attenuated MVA strain of vaccinia virus expressing JEV prM and E genes

Genes encoding the glycosylated precursor of the membrane (prM) and envelop e (E) proteins of a Korean strain of Japanese encephalitis virus (JEV) were inserted into the genome of the host-range restricted, highly attenuated, and safety-tested MVA strain of vaccinia virus. MVA recombinants containing the JEV genes, under strong synthetic or modified H5 vaccinia virus promot ers, were isolated. Synthesis of JEV prM and E proteins was detected by imm unofluorescence microscopy, flow cytometry, and polyacrylamide gel electrop horesis. Mice inoculated and boosted by various routes with either of the M VA recombinants produced JEV neutralizing antibodies, that had titres compa rable with those induced by an inactivated JEV vaccine, as well as haemaggl utination-inhibiting antibodies. Mice immunized with 2x10(6) infectious uni ts of MVA/JEV recombinants by intramuscular or intraperitoneal routes were completely protected against a 10(5) LD50 JEV challenge at 9 weeks of age. (C) 1998 Elsevier Science Ltd. All rights reserved.