There are currently over 100 COVID-19 vaccines going through trials, most of which focus on the use of antibodies, a powerful immune-system weapon.
A new paper published in Nature from Swiss, French, and American scientists identified an antibody taken from a patient infected with the SARS (severe acute respiratory syndrome) virus during the outbreak in 2003 that seems to neutralize COVID-19's infection potential.
Antibodies are produced by the immune-system in response to foreign material in the body. 25 antibodies were identified as potentially competent in detecting the COVID-19 virus and binding to its spike protein, the docking mechanism that allows the virus to infiltrate our cells. Eight of these were found to be able to bind both to free viruses and already infected cells.
One candidate, named S309 was shown to have particularly strong neutralizing activity against COVID-19, and by solving the crystal structure of S309, the authors demonstrated how the antibody binds to the viral spike protein while working in combination with another, less potent, antibody that targets a different site on the spike.
This synergistic activity could enhance neutralization while reducing the chance of resistant mutations emerging, the authors suggest.
The Killer T-Cell
Another weapon in the immune-system's arsenal are killer T-cells. These compounds help us fight some viruses, but throughout the COVID-19 pandemic their role as potentially helpful or benign has been unclear.
Two studies, according to Science, have found that the killer T-cells of COVID-19 positive patients have the potential to both identify and destroy the now famous virus. Moreover, the studies revealed that some people who have never been exposed to COVID-19 also harbor these T-cells—most likely because they were infected with another form of coronavirus in the past.