A team of researchers from the Superior Council of Scientific Investigations (CSIC) is seeking a vaccine for COVID-19 by using a gene for an antigen from the SARS-CoV-2 coronavirus itself to stimulate receptor immunity. The method involves placing the antigen gene in a synthetic DNA 'vehicle' (a plasmid) that can be introduced into the patient's body and induce protection against infection. The team is synthesizing the corresponding DNA molecules to be introduced into the vehicle, and in two months it could begin testing in mouse models.
This procedure has already been tested in a vaccine for canine leishmaniasis that is in phase IV, at the request of the European Medicines Agency for a manufacturing and marketing permit, according to the director of the study, the ad honorem research professor of the CSIC Vicente Larraga, from the Center for Biological Research-Margarita Salas.
This development of protective vaccine presents an additional advantage: the industrial scaling process of the vaccine candidate has already been carried out previously, which would significantly advance the industrial phase of manufacturing, human testing and subsequent production, if the test results were positive. With this, there are already three CSIC projects seeking a coronavirus vaccine, along with those led by Luis Enjuanes and Isabel Sola, and Mariano Esteban and Juan García Arriaza, both from the National Center for Biotechnology (CNB-CSIC).
"It is a novel recombinant DNA vaccine that introduces, in the animal to be vaccinated, instead of the attenuated parasite or a fragment thereof or a purified protein, the gene of a parasite antigen that induces protection against infection. "Larraga details.
The researcher explains that this vaccine uses as a vaccination vehicle a synthetic DNA plasmid (pPAL) that has been developed in his laboratory and that allows the integration of the gene of the chosen antigen of the parasite into the genetic material of the cells of the recipient mammal and the production by them of the antigen, which is then recognized by the immune system of the vaccinated animal and induces protection when natural infection occurs.
This procedure can also be used in the case of the SARS-CoV-2 virus, since it has been developed as a vehicle for mammals, including humans. In this case, the protein S (spike) of the virus surface and its S1 and S2 subunits, which are used by it to anchor and penetrate the membrane of the target cell, has been chosen as a possible vaccination protective antigen. .
"It is, therefore, a synthetic vaccine with a DNA vehicle in which the genes corresponding to the complete protein S of the virus and its subunits 1 and 2 will be introduced. At this moment, the DNA molecules are being synthesized corresponding to be introduced into the previously developed vehicle This process should be carried out throughout the months of May and June Next, its safety and efficacy against virus infection would be tested in the mouse model, either in animals transfected with the human ACE2 receptor or the like. If the results were positive, phases I and II of human testing would begin, "Larraga details.