Studies conducted with mice demonstrated that the vaccine against COVID-19 being developed by researchers at the Immunology Laboratory of the Institute of Tropical Medicine of the Faculty of Medicine of the University of São Paulo (FMUSP) is safe and effective in inducing the immune response against the pathogen and protect rodents from infection. The results were published in the magazine Scientific Reports
“Generally, when we talk about vaccines, we think about the inoculation of an attenuated or inactivated virus. However, we are using a more modern strategy that allows us to prioritize, in addition to efficiency and safety, greater plasticity of the formulation, that is, easier updating against variants of concern”, stated Gustavo Cabral de Miranda, researcher responsible for the project which is supported by FAPESP.
The strategy used by the FMUSP research group to develop the immunizer is based on the use of virus-like particles (VLPs). virus-like particles ). “This category of viral protein has characteristics similar to those of a virus, however, without the genetic material. This means that, while VLPs are recognized by the immune system, they do not present the risk of replicating or causing the disease”, says Cabral.
The researcher explains that the VLP can be the vaccine on its own, or – as in the case of the formulation being developed – bind to an antigen, a protein that activates the immune system, causing it to produce antibodies.
“Under specific laboratory conditions, these structural surface proteins have the ability to self-transform into VLPs. Then, they can be produced in laboratories using bacteria that act as mini-factories, stimulating this self-transformation. A second step is to inoculate the antigen, in the case of COVID-19, the spike protein. This greatly facilitates the entire process, allows greater flexibility and also makes the development of the vaccine cheaper”, says the researcher.
Another advantage of the Covid-19 vaccine, highlighted by Cabral, is the need for adjuvants, substances that enhance the immune response. “In this work both in testing in vitro as in vivo We put together strategies to try to make the formulation cheaper, using as few products as possible that were not developed in the laboratory. So much so that the immunizer does not need an adjuvant”, he said.
The researcher explains that in a vaccine formulation, in addition to the material that is part of or imitates the virus – in this case the VLPs – several other compounds are needed to stimulate the immune response. Among them, the main ones are adjuvants. The most common adjuvant is aluminum hydroxide, a salt that has been used for over a hundred years in vaccine development around the world. “Assembling a self-adjuvant technology (which does not need these compounds) gives us the chance to escape dependence on companies that produce adjuvants, in addition to making the formulation cheaper,” he said.
The FMUSP group of researchers also aims to produce knowledge to leverage a useful technological platform for the development of different vaccines. “This is because VLP technology is very flexible and allowed, for example, us to simply remove the antigen (in this case a piece of the SARS-CoV-2 protein) and replace it with a protein from the Zika virus. This is not just a hypothetical case, but something that we are also developing in our laboratory. Of course, it is not so simple, but it is possible to create a platform to develop a series of vaccines using this technology”, said Cabral.
This content was originally published in USP vaccine against Covid-19 has promising test results on the CNN Brasil website.
Source: CNN Brasil