Researchers work on the development of antibodies against the coronavirus

Produced in the blood of horses, the antibodies allow passive immunization to be offered to patients with severe COVID-19

Researchers from the Pelé Pequeno Príncipe Research Institute, the Center of Production and Immunological Research (CPPI), the State Health Department (Sesa) and the Federal University of Paraná (UFPR) are working on the development of antibodies against the coronavirus (SARS-CoV-2). The study immunizes horses for the production of anti-SARS-CoV-2 antibodies that will be extracted from the plasma of these animals, then modified and purified in the laboratory (see summary in the infographic).

The researcher who designed the study, Bonald Cavalcante de Figueiredo, explains that treatment with antibodies is called passive immunity because the patient receives the antibody instead of producing it. “The difference is that the active vaccine requires a time that goes from 15 to 30 days for the vaccinated person’s body to start producing the antibodies. Patients who are in severe COVID-19 condition usually do not have time to wait for immunity from an active vaccine. Our passive immunity option can be a solution for these people,” he details.

Figueiredo also says that the project has a second purpose, which is to innovate with a fast and much more complete test for the detection of SARS-CoV-2.

Development
In the first stage of the study, completed in July, the researchers defined what types of antibodies they would like to be produced in the horses’ blood. For that, they had to choose several parts of the virus that would be “attacked” by these antibodies. The targets chosen were the different parts of the Spike protein, and especially the one that links to a specific receptor called ACE2, which is located on the surface of cells, as it is the one that allows the virus to invade human cells. Based on tests carried out on the blood of people infected with SARS-CoV-2, they completed the first stage of the research by identifying which “small pieces of the virus”, technically called peptides, are efficient in stimulating the production of antibodies. These peptides were then produced in the laboratory.

At the beginning of August, the researchers started the second stage of the research, injecting these peptides, or “pieces” of laboratory manufactured viruses, into 19 horses of the CPPI. Upon contact with these peptides, horses are expected to produce high amounts of antibodies needed to neutralize SARS-CoV-2.

Next steps
After 70 days from the first injection, the researchers will draw blood samples from the animals and separate the plasma, which will undergo processing. It is at this stage that antibodies will be removed. Then, the antibodies will be cut, and a small portion will be kept in small bottles for use in patients with the active disease.

The small bottles with the “mini antibodies” will be tested (neutralization test) in the laboratory, using human cells exposed to the coronavirus and the “mini antibodies”. This is the third stage of the research. Proving the efficiency of these “mini antibodies”, the project will be submitted to the ethics committees for authorization and beginning of tests on patients (randomized clinical trials), the last stage of the research. “Theoretically, the patient with increasing viral load rates, and consequently with a worse clinical condition, could have this cycle interrupted after the injections of these mini antibodies,” highlights Figueiredo.

Additional benefit
As an additional benefit, the researchers are also working on building fast tests for COVID-19. “Even though we know that there are already many commercial tests, what we intend to do is innovate, creating a test that can reveal different types of immunities. In this innovation, we will have up to 12 test results per patient, representing the different parts of the virus that were recognized by antibodies detected in the patient. The results of these tests may also suggest how these patients will progress clinically,” informs the researcher.

Meet the team of researchers working on this project:
– Lauro Mera de Souza (coordinator)
– Matias Eliseo Melendez
– João Carlos Minozzo
– Juliana Ferreira de Moura
– Rubens Gusso
– Daniele Maria Ferreira
– Elizabeth Fernandes
– Libera Maria Dalla Costa
– Roberto Rosati
– Thiago D. Woiski
– Heloisa Komechen
– Bruno Cesar Antunes
– Ericson de Moura
– Bonald Cavalcante de Figueiredo

Click here, watch the video and learn more about this research project.

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