Attenuation of Tick-Borne Encephalitis Virus Using Large-Scale Random Codon Re-encoding

PLoS Pathogens

Lauriane de Fabritus¹  Xavier de Lamballerie¹  Ernest A Gould¹  Antoine Nougairède¹  Fabien Aubry² 

[1] Aix Marseille Université, IRD French Institute of Research for Development, EHESP French School of Public Health, EPV UMR_D 190 “Emergence des Pathologies Virales”, Marseille, France;Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France

关键词: RNA viruses;    Chikungunya virus;    Mouse models;    Tick-borne encephalitis virus;    Viral replication;    Attenuated vaccines;    Mammalian genomics;    Microbial mutation;   

DOI  :  10.1371/journal.ppat.1004738

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Large-scale codon re-encoding (i.e. introduction of a large number of synonymous mutations) is a novel method of generating attenuated viruses. Here, it was applied to the pathogenic flavivirus, tick-borne encephalitis virus (TBEV) which causes febrile illness and encephalitis in humans in forested regions of Europe and Asia. Using an infectious clone of the Oshima 5–10 strain ("wild-type virus"), a cassette of 1.4kb located in the NS5 coding region, was modified by randomly introducing 273 synonymous mutations ("re-encoded virus"). Whilst the in cellulo replicative fitness of the re-encoded virus was only slightly reduced, the re-encoded virus displayed an attenuated phenotype in a laboratory mouse model of non-lethal encephalitis. Following intra-peritoneal inoculation of either 2.105 or 2.106 TCID50 of virus, the frequency of viraemia, neurovirulence (measured using weight loss and appearance of symptoms) and neuroinvasiveness (detection of virus in the brain) were significantly decreased when compared with the wild-type virus. Mice infected by wild-type or re-encoded viruses produced comparable amounts of neutralising antibodies and results of challenge experiments demonstrated that mice previously infected with the re-encoded virus were protected against subsequent infection by the wild-type virus. This constitutes evidence that a mammalian species can be protected against infection by a virulent wild-type positive-stranded RNA virus following immunisation with a derived randomly re-encoded strain. Our results demonstrate that random codon re-encoding is potentially a simple and effective method of generating live-attenuated vaccine candidates against pathogenic flaviviruses.

【 授权许可】

CC BY