In 2003, a respiratory illness called Severe Acute Respiratory Syndrome (SARS) swept the globe. The condition, caused by a coronavirus, spread throughout two dozen countries, infecting 8,098 people and killing 774. Symptoms included a fever, headache, body aches, a dry cough, and pneumonia. Does this sound familiar to anyone else? Clearly, COVID-19 is operating on a much larger and more fatal scale than SARS. Yet since both diseases were caused by coronavirus strains, researchers wondered if prior patients might have protective antibodies. Blood testing found a potential result: antibody S309. Read the findings in Nature.
Researchers performed blood tests on a patient who contracted SARS during the 2003 epidemic. The results showed monoclonal antibodies within memory B cells.
To break it down:
Monoclonal antibodies are lab-developed antibodies cloned from an initial immune cell. They bind to antigens, or foreign invaders, in the body. These can be studied to understand how the immune system might act towards a specific bacteria or virus. In this case, researchers found that the antibodies targeted a distinct protein structure within coronaviruses. The virus harnesses this structure to fuse to and fill a cell with genetic material.
Memory B cells are cells that develop after an infection. An article in Frontiers in Immunology notes that these cells remember the antigen that they fought. So, memory B cells fight back against re-exposure or reinfections. Memory B cells can be extremely long-lasting.
Impact on COVID-19
One huge question is whether antibody S309 can prevent COVID-19 infection or reduce the condition’s severity. Testing shows that it can impair the protein that allows COVID-19 to enter cells. Additionally, researchers identified a unique element of antibody S309: it targets the virus’ binding site. This allows it to react to multiple strains of coronavirus, rather than just one.
Antibody S309 could be used in conjunction with other antibody therapies to protect against COVID-19. However, further research is needed to affirm this protective status. Vir Biotechnology is leading the charge on therapeutic development, testing, and potential future clinical trials.