Induction of Protective Immunity against Japanese Encephalitis in Mice by Immunization with a Plasmid Encoding Japanese Encephalitis Virus Premembrane and Envelope Genes

Abstract

A DNA vaccine plasmid containing the Japanese encephalitis (JE) virus premembrane (prM) and envelope (E) genes (designated pcDNA3JEME) was evaluated for immunogenicity and protective efficacy in mice. Two immunizations of 4-week-old female ICR mice with pcDNA3JEME by intramuscular or intradermal injections at a dose of 10 or 100 μg per mouse elicited neutralizing (NEUT) antibodies at titers of 1:10 to 1:20 (90% plaque reduction), and all immunized mice survived a challenge with 10,000 50% lethal doses of the P3 strain of JE virus. A single immunization with 100 μg of pcDNA3JEME did not elicit detectable NEUT antibodies but induced protective immunity. Spleen cells obtained from BALB/c mice immunized once with 10 or 100 μg of pcDNA3JEME contained JE virus-specific memory cytotoxic T lymphocytes (CTLs). BALB/c mice maintained detectable levels of memory B cells and CTLs for at least 6 months after one immunization with pcDNA3JEME at a dose of 100 μg. The CTLs induced in BALB/c mice immunized twice with 100 μg of pcDNA3JEME were CD8 positive and recognized mainly the envelope protein. These results indicate that pcDNA3JEME has the ability to induce a protective immune response which includes JE virus-specific antibodies and CTLs.

Mosquito Cells Infected with Japanese Encephalitis Virus Release Slowly‐Sedimenting Hemagglutinin Particles in Association with Intracellular Formation of Smooth Membrane Structures

“…Six strains of JEV were used in this study. The Nakayama and Beijing P3 strains have been described (23). The Beijing P1 strain, which had been passaged eleven times through suckling mouse brains (SMBs) and one time through Vero cells was provided by Dr. Robert E. Shope of Yale Arbovirus Research Unit, Yale University School of Medicine, Conn., U.S.A.…”

Structures and mechanisms in flavivirus fusion

“…They are also similar in their specific HA activities and fusion properties, both of which are mediated by the E protein. Their particulate nature and native antigenic structure make RSPs excellent vaccine candidates, as has been shown in a number of immunization studies in the TBE virus and other flavivirus systems using purified RSPs (Konishi et al, 1992b;Konishi et al, 1994;Heinz et al, 1995;Konishi et al, 1997b), as well as plasmid constructs (Phillpotts et al, 1996;Schmaljohn et al, 1997;Colombage et al, 1998;Konishi et al, 1998b;Aberle et al, 1999) and recombinant viruses Konishi et al, 1991;Pincus et al, 1992;Konishi et al, 1992a;Konishi et al, 1994;Fonseca et al, 1994;Konishi et al, 1997a;Colombage et al, 1998;Konishi et al, 1998a) that lead to the synthesis of RSPs after administration. Because their envelope glycoproteins have a native structure and are functionally active, RSPs are also an extremely valuable model for studying flavivirus envelope structure and function (see Sections VII.B, VII.F, and VII.G).…”

Generation and Characterization of a Mammalian Cell Line Continuously Expressing Japanese Encephalitis Virus Subviral Particles

“…Plasmids. The construction of pcJEME, which is a pcDNA3-based plasmid encoding the JEV (Nakayama strain) signal sequence of prM and the prM and E genes has been described previously (23). pcJEEP, which has a mutated pr/M cleavage site, was constructed from pcJEME by site-directed mutagenesis using the PCR method (13).…”