• Vaccine Name: Lassa fever Virus Vaccine MOPEVAC (Modified Mopeia virus expressing antigens of pathogenic arenaviruses)
• Target Pathogen: Lassa Fever Virus
• Target Disease: Lassa fever
• Manufacturer: Institut Pasteur
• Type: Live, attenuated vaccine
• Status: Research
• Host Species for Licensed Use: None
• Antigen: GPC (Salami et al., 2019)
• GPC gene engineering:
  • Type: Recombinant vector construction
  • Description: Multiple mutations in the ExoN site of MOPV NP generated a hyperattenuated strain (MOPVExoN6b). MOPVExoN6b was further modified to harbor the envelope glycoproteins of heterologous pathogenic arenaviruses, such as LASV. (Carnec et al., 2018)
  • Detailed Gene Information: Click Here.
• Immunization Route: subcutaneous injection

Monkey Response

• Vaccination Protocol: Four cynomolgus monkeys were immunized with 6 × 10^6 focus-forming units (FFU) 37 days before challenge with LASV (Josiah strain). Three animals were treated with an irrelevant vaccine and used as controls. A single dose of either vaccine was injected during the study. (Carnec et al., 2018)
• Immune Response: Blood samples were collected at several time points, and the activation of CD4+ and CD8+ T cells was measured after stimulation with LASV GPC-derived peptides. Our results showed that tumor necrosis factor alpha (TNF-α)-producing CD8+ and CD4+ T cells were induced 14 days after immunization in most immunized animals in response to LASV GPC-derived peptides. In one animal, GPC-specific CD8+ T cells were rather detected 30 days after immunization, while in another one, GPC-specific CD4 T cells circulated for 14 days postimmunization. Importantly, neutralizing antibodies specific for MOPEVACLAS were detected in the plasma of all immunized animals 23 days after immunization. Thus, a single shot of MOPEVACLAS was able to induce both cellular and humoral immune responses against LASV. (Carnec et al., 2018)
• Side Effects: Low-grade fever observed for all animals on the day of immunization (Carnec et al., 2018)
• Challenge Protocol: All animals were then submitted to a challenge with LASV injected subcutaneously (1,500 FFU) (Carnec et al., 2018)
• Efficacy: The four animals immunized with MOPEVACLAS survived the challenge. Three animals presented a fever from days 5 to 10, while the temperature of the fourth animal remained within the normal range. No other symptoms were recorded throughout the course of the challenge. Our results showed that MOPEVACLAS fully protects animals against a lethal challenge with LASV. Taken together, these results showed that the hyperattenuated MOPV-based LASV vaccine candidate is effective. (Carnec et al., 2018)