Vicente Larraga, ad Honorem Research Professor at the Center for Biological Research Margarita Salas, will develop a novel recombinant DNA vaccine against the SARS-CoV-2 virus that introduces, instead of the attenuated pathogen -or a fragment thereof- or a purified protein, the gene corresponding to a virus antigen that induces protection against infection by the virus.
The Molecular Parasitology Group led by Prof. Larraga has developed a vaccine with these characteristics against canine Leishmaniasis that is currently in Phase IV (application to the European Medicines Agency for a manufacturing and marketing permit). The vaccination vehicle developed in this laboratory and used by this vaccine is a synthetic DNA plasmid (pPAL), which allows the integration of the chosen antigen gene from the infectious organism into the genetic material of the cells of the recipient mammal. These cells will then produce the antigen, which will be recognized by the immunized system of the vaccinated individual and will induce protection upon natural infection. This novel vehicle has the additional advantage that it does not require the presence of adjuvants in the vaccine and has been designed for mammals, including humans, thus being free of sequences that may be toxic.
Thus, the same procedure can be used against the SARS-CoV-2 virus. In this case, the protein S of the virus surface, its S1 and S2 subunits, as well as the cell's ACE2 receptor binding fragment, have been chosen as possible vaccination protective antigens, as they are the regions used by SARS-CoV-2 to anchor and penetrate the target cell's membrane.
The DNA molecules corresponding to these selected antigens are currently being synthesized, which will be introduced into the previously developed vehicle. Their safety and efficacy against virus infection would then be tested in animal models, either in animals transfected with the human ACE2 receptor or similar. If the results were positive, phases I and II of human testing would begin. An additional advantage of the development of this vaccine is that the industrial scaling process of the vaccine candidate has already been carried out, which would significantly advance the industrial phase of manufacturing, human testing and subsequent production.
CSIC Press Release (in Spanish): link
Ministerio de Ciencia e Innovación Press Release (in Spanish): link