Beta-RBD-TM mRNA-LNP vaccine
RBD
The mRNA-RBD vaccine consists of a lipid nanoparticle (LNP) dispersion that encapsulates mRNA encoding an engineered form of the RBD of the Spike protein of the SARS-CoV-2 beta variant. The nucleoside modified mRNA (uridines are replaced with N1-methyl-pseudouridine) codes for the RBD linked to the transmembrane domain and the ‘intracellular’ domain of the Spike protein. The intracellular domain remains on the inside of the viral envelope when the viral particles are formed. This mRNA is translated to produce a membrane-anchored RBD, as we wanted the translated protein to be expressed and then presented in a manner analogous to the membrane-anchored presentation of translated whole spike mRNA vaccine. The mRNA is encapsulated in a unique Monash Institute of Pharmaceutical Sciences, Melbourne, Australia (MIPS) LNP formulation, using four lipids all of which have been used in FDA-approved products: DLin-MC3-DMA, cholesterol, DSPC and DMG-PEG 2000. The mRNA drug substance was manufactured by eTheRNA immunotherapies (Niel, Belgium), with the linear DNA template provided by MIPS. Final manufacture and LNP formulation were carried out in collaboration with IDT Australia. The administered vaccine was diluted to the required dose level with an isotonic tromethamine/sucrose buffer solution (IDT Australia Ltd) at the time of vaccination.