Studies conducted in mice have shown that the COVID-19 vaccine being developed by researchers at the University of São Paulo’s Medical School (FM-USP) in Brazil is safe and efficacious. The vaccine triggered a satisfactory immune response against the pathogen in the mice and protected them from infection. An article describing the results is published in the journal Scientific Reports.
“Most vaccines are based on attenuated or inactivated viruses, but our next-generation strategy enables us to prioritize not just safety and efficacy but also plasticity in the formulation so that the vaccine can easily be updated to combat variants of concern,” said Gustavo Cabral de Miranda, principal investigator for the project, which is supported by FAPESP and hosted by the Immunology Laboratory in the Institute of Tropical Medicine (IMT-FM-USP).
The strategy used by the researchers at FM-USP to develop the vaccine deploys virus-like particles (VLPs). “VLPs have similar characteristics to viruses but without viral genetic material, so although they’re recognized by the immune system, they cannot replicate or cause disease,” Cabral said.
VLPs can serve as vaccines on their own, or they can be conjugated with an antigen (a protein that stimulates the immune system to produce antibodies), as in this specific case. “Under certain conditions in the lab, structural surface proteins are capable of converting themselves into VLPs. They can be produced in the lab using bacteria that act as miniature factories to stimulate this transformation. A second step entails inoculation of the antigen, which is the spike protein in the case of COVID-19. This