Testing the people of a new Covid-19 vaccine developed in Brazil will begin this year. In August, Nature Communications have performed well in animal trials as reported in an article published.
Clinical trials of novel COVID-19 vaccine developed in Brazil to begin soon
Human testing of a new COVID-19 vaccine developed in Brazil will begin this year. It performed well in animal experiments, as reported in a paper Nature Communications in August. The scientists responsible for the vaccine have received new authorization from the National Health Surveillance Agency (ANVISA) to begin clinical trials.
Ricardo Tostes Gazzinelli said, "There are only some minor adjustments to the protocol of the study that need to be made before we submit it once again for approval to the National Research Ethics Council [CONEP]. We expect to begin clinical trials by the end of October." Agência, head of the Vaccine Technology Center (CTV-UFMG) at Federal University of Minas Gerais, told FAPESP. Gazzinelli is also a senior researcher at the Oswaldo Cruz Foundation (Fiocruz), the research arm of the Ministry of Health.
The Gazzinelli-led group combined two different SARS-CoV-2 proteins to develop the vaccine formulation: N (for the nucleocapsid containing the virus's genetic material) and part of the S (for the spike, the protein the virus uses for the vaccine). binds to invade human cells). The resulting chimeric molecule is called SpiN. The strategy aims to trigger a cellular immune response consisting of the production of defense cells (T lymphocytes) that specialize in recognizing and killing the new coronavirus. Such protection should remain effective even against new variants.
"The COVID-19 vaccines currently in use are primarily designed to trigger the production of neutralizing antibodies against the S protein and prevent the virus from infecting human cells. This is known as the humoral immune response. Many mutations in the S protein have weakened the ability of these antibodies to recognize this antigen. , whereas the N protein is better conserved in the new strains," he said.
According to Gazzinelli, who is also a visiting professor at the University of São Paulo Ribeirão Preto School of Medicine (FMRP-USP), the vaccine, based on the chimeric protein SpiN, does not trigger the production of neutralizing antibodies, but if given as a booster, both the humoral immunity produced by previous vaccination and It also provides double protection by stimulating cellular immunity.
challenge test
The animal experiments were carried out in the high biosafety laboratory at FMRP-USP, thanks to collaboration with João Santana da Silva and Luiz Tadeu Figueiredo, both professors there. The research was supported by FAPESP, the Ministry of Science, Technology and Innovation (MCTI) through the virus network (Rede Vírus), the Minas Gerais Research Fund Foundation (FAPEMIG) and the City of Belo Horizonte (the capital city of Minas Gerais).
The first step was to test the efficacy of the vaccine in mice genetically modified to express ACE2, the human protein to which the virus binds via its spike (S) to infect the host's cells. This model mimics the severe form of COVID-19.
Some mice were given two doses 21 days apart. Others took a placebo. One month later they were exposed to a high viral load intranasally. Vaccine them to the wild-type SARS-CoV-2 strain (isolated in China in 2019), the delta variant (India, 2020), and the omicron variant (South Africa, 2021).
In the control group given the placebo, 100% of animals infected with the [wild-type] Wuhan strain or delta . Mice exposed to Omicron did not die, but developed significant pathology in the lungs. In the vaccinated group, all animals survived infection by all three strains and lung tissue was much more preserved. Also, the viral load was 50 to 100 times lower." Julia Castro, PhD Candidate
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The next step involved testing the vaccine in a moderate disease model. To do this, scientists used hamsters that were naturally infected by the virus, but not very effectively. They were given two doses of the vaccine and exposed to the Wuhan or delta strain a month later. Compared to the control group, the vaccinated hamsters had approximately ten times lower viral load and fewer signs of lung damage.
Stability and security
A platform was established at CTV-UFMG to generate the chimeric protein SpiN in genetically modified bacteria. There also tests were carried out to ensure purity (no contaminants in the formulation) and stability (resistance at different temperatures).
According to Gazzinelli, who conducted safety and toxicity tests on mice, "The results showed that the vaccine remained viable for two weeks at room temperature and at least six months when stored at 4 °C."
According to Gazzinelli, clinical trials are divided into Phase I and II. Phase I is expected to vaccinate 80 patients to ensure the vaccine is safe for humans, while Phase II will include a group of 400 volunteers for vaccine safety testing as well as evaluation of the vaccine's immunogenicity – or, in other words, vaccine capacity. Stimulates an effective immune response. The trials will be held at UFMG's medical school and will be led by Helton Santiago and Jorge Pinto, both professors there. They plan to vaccinate people who have been given any of the current COVID-19 vaccines at least six months ago.
"This will be a booster shot. Volunteers in the control group will receive the AstraZeneca vaccine. We will then compare the levels of neutralizing antibodies to SARS-CoV-2 and T lymphocytes. We expect our formulation to trigger an even stronger cellular immune response." ' said Gazzinelli. Gotopnews.com