The Federal University of Paraná (UFPR) announced on Wednesday (23) that the vaccine against covid-19 is effective if administered in two doses. The first tests were done with mice in the pre-clinical phase.
During the work, the animals were divided into three groups: the first received immunization with particles of the bacterial polyhydroxybutyrate polymer (PHB) coated with specific parts of the Spike protein, which is the protein that allows the coronavirus (Sars-CoV-2) to infect our cells. In the second group, the particles with the viral protein were added to Freund’s Adjuvant, an antigen solution used as an immunopotentiator. The last individuals, belonging to the control group, received only the bacterial polyhydroxybutyrate (PHB).
A second dose of the same substances applied in each experimental group was administered 20 days later.
When analyzing the results, the scientists could see that the serum collection performed after the first immunization was not enough to produce antibodies in a different amount compared to the control group.
With the second immunization, there was an important production of antibodies compared to the control group. “Of seven animals in the group immunized with PHB-linked antigen, five showed a response at least 20 times greater than that of the control group. On average, the group had 54 times more antibodies against the antigen than the control group,” said Marcelo Müller dos Santos , professor in the Department of Biochemistry and Molecular Biology at UFPR and one of the authors of the study.
Regarding the addition of Freund’s adjuvant, there was no effect on the immune response against PHB particles loaded with antigen. According to Santos, the data from this preclinical trial were a first step and showed that it is possible that PHB particles loaded with antigens are used against covid-19 and other viral diseases.
Now, according to the researchers, the next step is to analyze whether intranasal immunization is efficient. If the results are positive, the scientists will try to identify whether the sera of the immunized animals can neutralize the infection of the new coronavirus in cell culture, a fundamental factor to prove the effectiveness of the immunizer. .