The universal flu vaccine is a step closer say scientists who have discovered an antibody which interferes with the flu virus’ ability to pass on its genetic material to a host cell.
Researchers from the Scripps Research Institute have found that CR8020 powerfully neutralises a range of human-affecting flu viruses in lab-dish tests and in mice. This builds on previous work where they discovered CR6261 has a similar effect. The hope is that they could be combined into a vaccine, and used as a passive immunotherapy approach.
“This would mainly be useful as a fast-acting therapy against epidemic or pandemic influenza viruses,” said Ian Wilson, professor of structural biology and senior author of the paper published in Science.
“The ultimate goal is an active vaccine that elicits a robust long-term antibody response against those vulnerable epitopes, but developing that is going to be a challenging task.”
Researchers grew crystals of the new antibody CR8020 bound to a mushroom-shaped haemagglutinin (HA) protein from a deadly strain of H3N2, a strain of flu that killed over a million people in Asia in the 1960s.
Using x-ray crystallography techniques, they determined the antibody’s structure and its precise epitope or a binding site on the HA.
“It’s even lower on the HA stalk than the CR6261 epitope; in fact it’s closer to the viral envelope than any other influenza antibody epitope we’ve ever seen,” said Damian Ekiert, a graduate student working in Wilson’s lab.
In animal tests, the antibody can prevent or cure a broad variety of influenza viruses, including seasonal and potentially pandemic strains. In mice, an injections of the antibody CR6261 could prevent or cure an otherwise-lethal infection be about half of all flu viruses. Researchers subsequently looked for an antibody that could neutralise the remaining flu viruses – CR8020. CR6261 is about to begin tests in human volunteers, and it is expected similar trials of CR8020 will begin soon.