• Vaccine Name: Marburg Virus Vaccine mVLP Poly I:C Adjuvant
• Target Pathogen: Marburg Virus
• Target Disease: Hemorrhagic fever
• Type: Recombinant vector vaccine
• Status: Research
• Host Species for Licensed Use: None
• Antigen: Marburg Virus (MARV) glycoprotein, MARV nucleoprotein, MARV Matrix Protein VP40 (Dye et al., 2016)
• VP40 gene engineering:
  • Type: Recombinant vector construction
  • Description:
  • Detailed Gene Information: Click Here.
• GP from Marburg virus Ravn gene engineering:
  • Type: Recombinant vector construction
  • Description:
  • Detailed Gene Information: Click Here.
• NP from Marburgvirus Ravn gene engineering:
  • Type: Recombinant vector construction
  • Description:
  • Detailed Gene Information: Click Here.
• Preparation: For a generation of the MARV VLPs, the MARV GP, NP and VP40 genes were inserted into a single baculovirus vector system for expression in insect cells Sf9 insect cells were infected with the single recombinant baculovirus, and the VLPs were recovered from the culture supernatants by high-speed centrifugation, purified on sucrose gradients, and resuspended in phosphate buffered saline (PBS), as previously described. Total proteins in the VLP preparations were determined and the VLPs were analyzed by SDS-PAGE/Western blotting and ELISA for filovirus protein content and identity, immunogenicity in mice and endotoxin levels. (Dye et al., 2016)
• Immunization Route: subcutaneous injection

Macaque Response

• Vaccination Protocol: Thirteen macaques received intramuscular injections in the caudal thigh muscle containing 3 mg (total protein) of MARV VLPs and 0.5 mg/kg of polyI:C adjuvant. The three control animals received injections of one of the adjuvants only. Immunizations were performed on study days 0, 42, and 84. (Dye et al., 2016)
• Immune Response: Cynomolgus macaques were vaccinated with MARV VLPs on study days 0, 42, and 84 and serum antibody titers against purified MARV GP and VP40 were determined for each animal every two to three weeks (study days 0, 14, 28, 42, 56, 70, 84 and 105). Control animals, which were vaccinated with polyI:C adjuvant alone, did not generate any antibody responses to either MARV GPdTM or VP40 (below the limit of detection at a 1:100 dilution of serum). The vaccinated animals exhibited similar kinetics of antibody responses to both antigens, with detectable antibody titers at day 14, which waned slightly at day 42 and increased again after the second and third vaccinations were administered on study days 42 and 84. Animals vaccinated with MARV VLPs with polyI:C exhibited similar responses to the protective GP antigens (p = 0.6006). Animals vaccinated with MARV VLPs and polyI:C had higher responses to the VP40 antigen than those vaccinated with MARV VLP and QS-21, specifically at the later time points of days 70, 84 and 105 post vaccination (p = 0.0057) (Dye et al., 2016)
• Side Effects: In Groups 1, 2 and 4, the macaques vaccinated with MARV VLPs and challenged via either aerosol or SQ route, there were no animals with visible clinical signs of filovirus infection. The adjuvant only control macaques presented with typical clinical signs of filovirus infection in macaques. Animal 16-P-S, which was vaccinated with polyI:C alone and challenged by the SQ route exhibited severe depression, moderate rash, and no food intake at day 10 post challenge. (Dye et al., 2016)
• Challenge Protocol: MARV was grown on Vero cells (6 total passages) and enumerated using standard plaque assay. Administration of the virus challenge was performed on study day 112 with the challenge material administered in the subcutaneous (SQ) tissues of the left thigh of each animal or via the aerosol route, as previously described. The target challenge dose for both SQ and aerosol exposure was 1000 plaque-forming units (pfu)/mL. For the SQ challenge, each macaque received 0.5 mL of challenge stock MARV-Musoke, which upon back-titration revealed an actual challenge dose of 315 pfu/macaque. For aerosol challenge, each macaque was exposed to 10 mL of challenge stock MARV-Musoke using a previously described methodology, and the air in the aerosolization chamber was sampled during each exposure to calculate the actual inhaled dose of virus that each animal received. This revealed that the inhaled dose ranged between 40–135 pfu/macaque. (Dye et al., 2016)
• Efficacy: Vaccination of cynomolgus macaques with MARV VLP with polyI:C adjuvant provided complete protection against challenge with aerosolized MARV-Musoke. (Dye et al., 2016)