Partial cross-protection between Japanese encephalitis virus genotype I and III in mice

Abstract

Genotype III (GIII) Japanese encephalitis virus (JEV) predominance has gradually been replaced by genotype I (GI) over the last 20 years in many Asian countries. This genotype shift raises concerns about the protective efficacy of Japanese encephalitis (JE) vaccines, as all of the currently licensed JE vaccines are derived from GIII strains. In this study, we conducted vaccination-challenge protection assays to evaluate the cross-protective efficacy of GI- or GIII-derived vaccines against the challenge of a heterologous genotype using a mouse challenge model. Titration of the neutralizing antibodies elicited by SA14-14-2 live-attenuated JE vaccine (SA14-14-2 vaccine), a GIII-derived vaccine, indicated that the titer of neutralizing antibodies specific to heterologous genotype GI stain was significantly lower than that specific to homologous genotype GIII strain in both pigs and mice immunized with the SA14-14-2 vaccine. Vaccination of mice with SA14-14-2 vaccine or a GIII-inactivated vaccine at high and medium doses completely protected vaccinated mice against challenge with the homologous genotype GIII strains, but failed to provide the vaccinated mice complete protection against the challenge of heterologous genotype GI strains. The protection rates against GI strain challenge were 60%–80%, showing that these vaccines were partially protective against GI strain challenge. Additionally, vaccination of mice with a GI-inactivated vaccine conferred 100% protection against the challenge of homologous genotype GI strains, but 50%–90% protection against the challenge of heterologous genotype GIII strains, showing a reduced protective efficacy of a GI-derived vaccine against GIII strain challenge. Overall, these observations demonstrated a partial cross-protection between GI and GIII strains and suggested a potential need for new JE vaccine strategies, including options like a bivalent vaccine, to control both genotype infection.

A Metagenomic Analysis of Mosquito Virome Collected From Different Animal Farms at Yunnan–Myanmar Border of China

“…The previous studies indicate that GI strains have higher replication efficiency in birds and pigs than GIII strains ( Fan et al, 2019 ; Li et al, 2020 ), and the emergence and continuous circulation of GI strains could be permanent threats for pigs as well as for poultry. Development of precautionary measures, such as GI vaccine, in advance is needed to avoid future outbreaks due to this newly emerging genotype ( Wei et al, 2019 ).…”

Japanese encephalitis in Bali, Indonesia: ecological and socio-cultural perspectives

“…The E protein is a major structural protein that contains the receptor-binding domain and the neutralization epitopes. Additionally, Wei et al [ 11 ] also argued that the amino acid variation in the E protein of the JEV may affect virulence and antigenicity.…”

Rapid and sensitive RPA-Cas12a-fluorescence assay for point-of-care detection of African swine fever virus

“…Recently, a variety of laboratory tools has emerged to solve the immediate problems for better detection of ASFV, such as serodiagnosis (immunoelectroosmophoresis, IEOP) test [21], antigen ELISA [22], fluorescent antibody test (FAT) [23], immunochromatography test strip (ICTS) [24]) and molecular tools (PCR, RPA [25], multiplex RT-PCR [26] and qPCR [27,28]). The OIE has recommended several ASFV detection methods, including virus isolation, fluorescence antibody test (FAT) and conventional PCR or real-time PCR [29] in 2018.…”