Finding an effective way to fight COVID-19 is by far the biggest .challenge faced by the scientific community currently. While several methods have shown promise, some have failed to live up to expectations. In the midst of this, some researchers are pinning their hopes on an antibody known as S309 discovered in the blood of a patient who survived Severe acute respiratory syndrome (SARS) in 2003.
In laboratory studies, it has been found that S309 inhibits several viruses related to the SARS virus, including the SARS-CoV2 virus that causes COVID-19. The testing and development of the antibody are on fast track with clinical trials being a possibility. "We still need to show that this antibody is protective in living systems, which has not yet been done," said David Veesler, senior author of the study, in a statement.
Finding Monoclonal Antibodies
The researchers discovered various monoclonal antibodies of significance from memory B cells in the survivor's body. A memory B cell is a type of cell formed in the body after an infection or illness. They often remember the pathogen that they combated against for a long time, and at times, for a lifetime. So when there is a re-infection in the future by the same virus or bacteria, or pathogens similar to them, they mount defensive immune response.
Amongst the monoclonal antibodies found within the memory B cells of the SARS survivor, several are aimed at the key protein structures of the coronaviruses. This structure is vital when it comes to the ability of the coronavirus to gain entry into the human body by recognizing receptors on a cell. Following which it binds with it and introduces its genetic material into the cell. As the media coverage surrounding coronaviruses has informed most of us, the spikes on the crown of the coronaviruses are important in their infecting mechanism.
Key Antibody Discovered
During the course of the research, the antibody, S309, was found to be lethal in honing in and incapacitating the spike protein that leads the charge in the invasion of cells. It also successfully neutralizes the SARS CoV-2 or the novel coronavirus by attacking a portion of the spike protein close to the area where it attaches to the host cell.
Using binding assays and cryo-electronmicroscopy, the scientists discovered that S309 could recognize the binding area on the coronavirus that is common to several viruses other than COVID-19 and SARS viruses, but also sarbocoviruses— Severe acute respiratory syndrome-related coronaviruses. It is perhaps due to this ability that this antibody can counter related coronaviruses.
Cocktail Approach for Better Results
In addition to the effectiveness of S309 antibody, it was also found that combining the antibody with other relatively weaker monoclonal antibodies identified in the SARS survivor's body, amplified the neutralizing effect on the SARS CoV-2 coronavirus.
According to the researchers, the multi-cocktail method could enable the limitation of the coronavirus' capacity to form mutants, which can slip under single-ingredient antibody treatment.
The authors expressed hope that these results could encourage the use of S309 antibody. This can be done using S309 alone, or in combination with others. It could serve as a preventive option for individuals with high-risk of exposure to the COVID-19 coronavirus or as a therapeutic option for those after exposure to counter or treat the infection.
