New antibody weapons against Marburg virus found

Scientists have identified new immune molecules that protect against deadly Marburg virus, a relative of Ebola virus.
"These antibodies attack a new site on Marburg virus we had not seen before," said Erica Ollmann Saphire, senior author of the new study, professor at The Scripps Research Institute (TSRI) and director of the Viral Hemorrhagic Fever Immunotherapeutic Consortium.
The new antibodies identify and neutralise Marburg virus which has a mortality rate of up to 90 per cent.
Currently, there are no vaccines or treatments specifically for Marburg infections.
The new study builds on previous work in Saphire's lab which found a molecular structure that Marburg virus uses to attach to and enter host cells.

To defeat Marburg virus, scientists are looking for vulnerable sites on the virus's surface where an antibody can bind.

Previous research, including trials with the experimental ZMappTM treatment, shows that mixtures or 'cocktails' of antibodies can block Ebola virus from infecting new cells and alert the immune system to the presence of the infection.
It's thought that a similar cocktail strategy could work against Marburg virus.
Antibodies against one site on Marburg were found in a study by Vanderbilt University and TSRI earlier this year, but complementary antibodies needed against other sites remained to be discovered.
In the new study, TSRI researchers designed proteins which elicited new antibodies developed at Emergent BioSolutions.

Other antibodies in the study were independently identified at Mapp Biopharmaceutical and Integrated Biotherapeutics, which collaborated with TSRI for molecular analysis.
Some of the new antibodies target a new site on Marburg virus not seen before - a wing-like feature attached to the base of the virus.
Antibodies against this newly discovered site protected 90 to 100 per cent of infected animal models from lethal infection.
Some antibodies discovered in the new study are also able to cross-react with Ebola virus and its four relatives in the Ebolavirus genus, researchers said.
"We expect both Marburg virus and Ebola virus to emerge again and to acquire new mutations," said TSRI Research Assistant Marnie Fusco, first author of the new study.

"The cross-reactive antibodies could be used as diagnostics for newly emerging strains," Fusco said.