University of Pittsburgh School of Medicine scientists have isolated the smallest biological molecule to date that completely and specifically neutralizes the SARS-CoV-2 virus, which is the cause of COVID-19. This antibody component, which is 10 times smaller than a full-sized antibody, has been used to construct a drug — known as Ab8 — for potential use as a therapeutic and prophylactic against SARS-CoV-2.
The researchers report today (September 14, 2020) in the journal Cell that Ab8 is highly effective in preventing and treating SARS-CoV-2 infection in mice and hamsters. Its tiny size not only increases its potential for diffusion in tissues to better neutralize the virus, but also makes it possible to administer the drug by alternative routes, including inhalation. Importantly, it does not bind to human cells — a good sign that it won’t have negative side-effects in people.
Ab8 was evaluated in conjunction with scientists from the University of North Carolina at Chapel Hill (UNC) and University of Texas Medical Branch (UTMB) at Galveston, as well as the University of British Columbia and University of Saskatchewan.
“Ab8 not only has potential as therapy for COVID-19, but it also could be used to keep people from getting SARS-CoV-2 infections,” said co-author John Mellors, M.D., chief of the Division of Infectious Diseases at UPMC and Pitt. “Antibodies of larger size have worked against other infectious diseases and have been well tolerated, giving us hope that it could be an effective treatment for patients with COVID-19 and for protection of those who have never had the infection and are not immune.”