Second generation mRNA Marburg vaccine: Formulation development of mRNA-lipid nanoparticles with TLR9 agonist CpG oligonucleotide adjuvant

CPI RNA Vaccines 2023 -- A vaccine against Marburg virus is being developed using a self-amplifying messenger RNA (sa mRNA) for the Marburg Glycoprotein (MARV GP) antigen. The vaccine comprises the sa mRNA encapsulated into a lipid nanoparticle (LNP) for protection of the RNA and cellular delivery. As a further development, we are investigating incorporating Toll-like receptor (TLR) adjuvants into the MARV GP sa mRNA-LNPs to enhance the immune response. Using a microfluidic system, MARV GP sa mRNA-LNPs are being formulated with Toll receptor (TLR) agonist adjuvants to determine if these adjuvants can boost LNP vaccine immune response. Formulation of LNPs with the TLR9 DNA agonist CpG oligonucleotide (ODN) poses issues with total nucleic acid load, to ensure efficient encapsulation of the sa RNA along with the CpG ODN adjuvant. Hence, to optimise the encapsulation of sa mRNA and CpG ODN, we have run a Design of Experiment (DoE) study. The optimised formulation was used to produce MARV GP sa mRNA-CpG-LNPs for in vivo testing.