A Vaccine Platform against Arenaviruses Based on a Recombinant Hyperattenuated Mopeia Virus Expressing Heterologous Glycoproteins

Abstract

Several Old World and New World arenaviruses are responsible for severe endemic and epidemic hemorrhagic fevers, whereas other members of the family are nonpathogenic. To date, no approved vaccines, antivirals, or specific treatments are available, except for Junín virus. However, protection of nonhuman primates against Lassa fever virus (LASV) is possible through the inoculation of the closely related but nonpathogenic Mopeia virus (MOPV) before challenge with LASV. We reasoned that this virus, modified by using reverse genetics, would represent the basis for the generation of a vaccine platform against LASV and other pathogenic arenaviruses. After showing evidence of exoribonuclease (ExoN) activity in NP of MOPV, we found that this activity was essential for multiplication in antigen-presenting cells. The introduction of multiple mutations in the ExoN site of MOPV NP generated a hyperattenuated strain (MOPV) that is (i) genetically stable over passages, (ii) has increased immunogenic properties compared to those of MOPV, and (iii) still promotes a strong type I interferon (IFN) response. MOPV was further modified to harbor the envelope glycoproteins of heterologous pathogenic arenaviruses, such as LASV or Lujo, Machupo, Guanarito, Chapare, or Sabia virus in order to broaden specific antigenicity while preserving the hyperattenuated characteristics of the parental strain. Our MOPV-based vaccine candidate for LASV, MOPEVAC, was used in a one-shot immunization assay in nonhuman primates and fully protected them from a lethal challenge with LASV. Thus, our hyperattenuated strain of MOPV constitutes a promising new live-attenuated vaccine platform to immunize against several, if not all, pathogenic arenaviruses. Arenaviruses are emerging pathogens transmitted to humans by rodents and responsible for endemic and epidemic hemorrhagic fevers of global concern. Nonspecific symptoms associated with the onset of infection make these viruses difficult to distinguish from other endemic pathogens. Moreover, the unavailability of rapid diagnosis in the field delays the identification of the virus and early care for treatment and favors spreading. The vaccination of exposed populations would be of great help to decrease morbidity and human-to-human transmission. Using reverse genetics, we generated a vaccine platform for pathogenic arenaviruses based on a modified and hyperattenuated strain of the nonpathogenic Mopeia virus and showed that the Lassa virus candidate fully protected nonhuman primates from a lethal challenge. These results showed that a rationally designed recombinant MOPV-based vaccine is safe, immunogenic, and efficacious in nonhuman primates.

Quadrivalent VesiculoVax vaccine protects nonhuman primates from viral-induced hemorrhagic fever and death

“…Three vaccines expressing the LASV glycoprotein precursor (GPC) have shown complete protection in NHPs against the prototype lineage IV Josiah strain of LASV. These include a recombinant vaccine based on the related Mopeia arenavirus (19), a DNA vaccine (20), and a rVSVΔG-based vaccine (21,22). Importantly, no LASV vaccine has been evaluated in NHPs against the lineage II or III LASVs currently circulating in Nigeria or any other lineage of LASV.…”

Arenaviridae exoribonuclease presents genomic RNA edition capacity

“…The MOPV strain AN21366 (JN561684 and JN561685) was used to establish the reverse genetics system for MOPV. The detailed procedures for virus rescue, production, titration and infection of Vero E6 cells (VERO C1008 [Vero 76, clone E6, Vero E6] ATCC® CRL-1586™ (ATCC, LGC Standards, Molsheim, France) are described in [44]. In brief, the recombinant NP-exo WT and mutant (D390A/G393A) MOPV were used to infect Vero E6 cells using a MOI of 0.01.…”

“…For RNA quantification, viral RNA were extracted from cell culture supernatants (Qiagen, Courtaboeuf, France) and quantification was performed with the EuroBioGreen qPCR Mix Lo-ROX (Eurobio, Les Ulis, France), using an in house developed assay with 5'-CTTTCCCCTGGCGTGTCA-3' and 5'-GAATTTTGAAGGCTGCCTTGA-3' primers. Deep sequencing analysis of viral genomes was performed as described in [44].…”

Immunogenicity of a protective intradermal DNA vaccine against lassa virus in cynomolgus macaques

“…Several preclinical LASV vaccine candidates with varying degrees of protection in nonhuman primate (NHP) models of LASV infection have been reported in the literature, and these vaccines have generally been based on recombinant, replication-competent viral vector platforms such as VSV-LASV, YF17D/LASV, and MOPV/ LASV. [9][10][11] A DNA vaccine approach has the potential to address many challenges with viral vectored approaches in that they do not generate anti-vector responses allowing for repeated boosting, and they are non-replicating and nonintegrating. 12 Unlike conventional inactivated or subunit vaccines, DNA-based vaccines produce robust immune responses that are both cellular and humoral in nature due to their mimicry of natural infection pathways.…”