Advanced Safety and Genetic Stability in Mice of a Novel DNA-Launched Venezuelan Equine Encephalitis Virus Vaccine with Rearranged Structural Genes

Abstract

The safety and genetic stability of V4020, a novel Venezuelan Equine Encephalitis Virus (VEEV) vaccine based on the investigational VEEV TC-83 strain, was evaluated in mice. V4020 was generated from infectious DNA, contains a stabilizing mutation in the E2-120 glycoprotein, and includes rearrangement of structural genes. After intracranial inoculation (IC), replication of V4020 was more attenuated than TC-83, as documented by low clinical scores, inflammation, viral load in brain, and earlier viral clearance. During the first 9 days post-inoculation (DPI), genes involved in inflammation, cytokine signaling, adaptive immune responses, and apoptosis were upregulated in both groups. However, the magnitude of upregulation was greater in TC-83 than V4020 mice, and this pattern persisted till 13 DPI, while V4020 gene expression profiles declined to mock-infected levels. In addition, genetic markers of macrophages, DCs, and microglia were strongly upregulated in TC-83 mice. During five serial passages in the brain, less severe clinical manifestations and a lower viral load were observed in V4020 mice and all animals survived. In contrast, 13.3% of mice met euthanasia criteria during the passages in TC-83 group. At 2 DPI, RNA-Seq analysis of brain tissues revealed that V4020 mice had lower rates of mutations throughout five passages. A higher synonymous mutation ratio was observed in the nsP4 (RdRP) gene of TC-83 compared to V4020 mice. At 2 DPI, both viruses induced different expression profiles of host genes involved in neuro-regeneration. Taken together, these results provide evidence for the improved safety and genetic stability of the experimental V4020 VEEV vaccine in a murine model.

Zika virus infects pericytes in the choroid plexus and enters the central nervous system through the blood-cerebrospinal fluid barrier

“…Four-to six-week-old mice of both sexes were anesthetized under isoflurane and infected subcutaneously with 1000 p.f.u of virus (100% lethal in Ifnar-/or in AG129 mice) diluted in PBS at the rear foot pad. Clinical scoring was performed as described in elsewhere [71] In situ chromogenic RNA hybridization (i.e., RNAScope assay)…”

Live-Attenuated CHIKV Vaccine with Rearranged Genome Replicatesin vitroand Induces Immune Response in Mice

“…In another study, we also prepared a rearranged V4020 vaccine from the alphavirus vaccine TC83 for Venezuelan equine encephalitis virus (VEEV) [35]. V4020 vaccine was safe, immunogenic, and efficacious in mice and non-human primates [35, 41, 42] suggesting genetic rearrangement can be used for distinct alphavirus vaccines to improve safety.…”

Lassa Virus Vaccine Candidate ML29 Generates Truncated Viral RNAs Which Contribute to Interfering Activity and Attenuation

“…Following acclimation, mice were inoculated intracranially (IC) through the foramen magnum with 10 3 PFU (plaque forming units) of ML29, the qRT-PCR equivalent dose of ML29P50 (approximately a 1 to 20 dilution of the stock), or sterile PBS for mock treatment in a total volume of 10 µL as described [ 11 , 48 ]. Mice were observed daily for up to two weeks for survival, weight, and clinical score based on a composite of grooming, adjusted grimace scale, activity, and neurological manifestations as described [ 13 , 49 ].…”