Japanese encephalitis (JE) is the most common form of viral encephalitis that appears in the form of frequent epidemics of brain fever throughout Southeast Asia, China and India. The disease is caused by a Flavivirus named Japanese encephalitis virus that is spread to humans by mosquitoes. An internationally approved mouse brain-derived inactivated vaccine has been available that is relatively expensive, gives immunity of uncertain duration and is not completely safe. Cell culture-derived inactivated and attenuated JE vaccines are in use in China, but these are not produced as per the norms acceptable in most countries. Several new promising JE vaccine candidates have been developed, some of which are under different stages of clinical evaluation. These new candidate JE vaccines have the potential to generate long-lasting immunity at low cost.
Domain III of Japanese encephalitis virus (JEV) envelope protein (E-DIII) was synthesized in E. coli as a fusion protein containing maltose-binding protein (MBP-E-DIII) or six contiguous histidine residues (His-E-DIII) at its N-terminus. MBP-E-DIII was found both in the soluble as well as the insoluble fraction of the bacterial lysate, while His-E-DIII was found exclusively in the inclusion bodies. These purified proteins were examined in mice for their immunogenicity in presence of an aluminium hydroxide based-adjuvant Alhydrogel and Freund's adjuvant. While both proteins generated anti-JEV antibodies that neutralized JEV activity in vitro, His-E-DIII generated higher antibody titers than MBP-E-DIII. Mice immunized with His-E-DIII in presence of Alhydrogel generated antibody titers similar to those induced by the commercial vaccine and protected mice against lethal JEV challenge.
We have previously shown that immunization of mice with plasmid pMEa synthesizing Japanese encephalitis virus (JEV) envelope protein induced anti‐JEV humoral and cellular immune responses. We now show that intra‐muscular co‐administration of mice with pMEa and pGM‐CSF, encoding murine granulocyte‐macrophage colony‐stimulating factor or pIL‐2, encoding murine interleukin‐2 given 4 days after pMEa, augmented anti‐JEV antibody titers. This did not enhance the level of protection in immunized mice against JEV. However, intra‐dermal co‐administration of pMEa and pGM‐CSF in mice using the gene gun, enhanced anti‐JEV antibody titers resulting in an increased level of protection in mice against lethal JEV challenge.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.