A Japanese Encephalitis Virus Peptide Present on Johnson Grass Mosaic Virus-Like Particles Induces Virus-Neutralizing Antibodies and Protects Mice against Lethal Challenge

Abstract

Protection against Japanese encephalitis virus (JEV) is antibody dependent, and neutralizing antibodies alone are sufficient to impart protection. Thus, we are aiming to develop a peptide-based vaccine against JEV by identifying JEV peptide sequences that could induce virus-neutralizing antibodies. Previously, we have synthesized large amounts of Johnson grass mosaic virus (JGMV) coat protein (CP) in Escherichia coli and have shown that it autoassembled to form virus-like particles (VLPs). The envelope (E) protein of JEV contains the virus-neutralization epitopes. Four peptides from different locations within JEV E protein were chosen, and these were fused to JGMV CP by recombinant DNA methods. The fusion protein autoassembled to form VLPs that could be purified by sucrose gradient centrifugation. Immunization of mice with the recombinant VLPs containing JEV peptide sequences induced anti-peptide and anti-JEV antibodies. A 27-amino-acid peptide containing amino acids 373 to 399 from JEV E protein, present on JGMV VLPs, induced virus-neutralizing antibodies. Importantly, these antibodies were obtained without the use of an adjuvant. The immunized mice showed significant protection against a lethal JEV challenge.Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus responsible for acute encephalitis in humans, with fatality rates ranging from 20% to as high as 50%. The virus is active in a vast geographic area that includes India, China, Japan, and almost all of Southeast Asia. As many as 50,000 cases of JEV infection are reported from these areas every year, of which about 10,000 result in fatality. A high proportion of survivors have serious neurologic and psychiatric sequelae (34). A mouse brain-grown, formalin-inactivated vaccine is available internationally that has many limitations; it is expensive to produce, does not provide long-term immunity, and may cause allergic reactions because of the inclusion of murine encephalogenic basic protein or gelatin stabilizer (1,20,25,27). Thus, there is a need to produce an alternate vaccine that may be safer and cheaper.JEV infection of host cells produces three structural and seven nonstructural proteins. One of these, the E protein, is the major envelope protein of the virion. This protein is believed to play an important role in a number of processes, including viral attachment, membrane fusion, and entry into the host cell. In response to JEV infection, the host produces virus neutralizing antibodies and cytotoxic T cells (CTLs). The principal target for the neutralizing antibodies is the E protein.It has been shown that protection against JEV infection is mainly antibody dependent, and virus-neutralizing antibodies alone are sufficient to impart protection (10, 18). Peptide(s) from JEV E protein that forms the virus-neutralizing epitope(s) could, therefore, be used for inducing JEV-neutralizing antibodies.Recent findings suggest that presentation of peptides in a highly ordered aggregate form can result in enhanced immune responses (12). Johnson grass m...

Immunogenicity and protective efficacy of the E. coli-expressed domain III of Japanese encephalitis virus envelope protein in mice

“…This is in contrast to a report where amino acids 303-396 of JEV E protein fused to trpE protein of E. coli did not elicit any virus-neutralizing antibodies in mice [10]. However, present Wndings corroborate previous observations where amino acid 373-399 of JEV E protein representing a part of JEV E-DIII, expressed as fusions with the coat protein of Johnson Grass Mosaic Virus [15] or GST [16] elicited moderate titers of JEV-neutralizing antibodies.…”

Recombinant newcastle disease virus capsids displaying enterovirus 71 VP1 fragment induce a strong immune response in rabbits

“…Previously, these mice did not respond to the malaria peptide (M3) alone suggesting that the fusion of a molecular carrier BB was able to provide T-helper cells for the antibody production [Sjolander et al, 1997]. Saini and Vrati [2003] on the other hand, have demonstrated that the fusion of Japanese encephalitis virus (JEV) E protein-derived peptides to the C-terminally truncated coat protein of Johnson grass mosaic virus (JGMV) induced neutralizing antibodies in mice and protected the animals from the lethal challenge by JEV even in the absence of adjuvants.…”

Vaccinia Virus Recombinant Expressing an 87-Kilodalton Polyprotein That Is Sufficient To Form Astrovirus-Like Particles

“…In this way, in the future, they might facilitate the generation of an effective vaccine against this virus, as VLPs might induce an immune response similar to that elicited by inactivated virus (20). However, further experimentation is required to evaluate the true significance of our finding on the biology of the HAstV.…”