While there are no drugs available to treat Ebola, the new approach involves transfusing patients with blood plasma donated by survivors, which contains antibodies against the virus.
Clinical trials of convalescent plasma therapy (CPT) have started in Liberia, and are due to begin soon in Guinea and Sierra Leone, Nature.com reported.
If the therapy works, the approach could quickly be scaled up.
Success would also raise awareness of CPT's potential to treat other new and emerging infectious diseases for which there are no readily available effective drugs or vaccines, such as SARS, avian influenza and Middle East respiratory syndrome (MERS), researchers said.
"Clinical trials of convalescent plasma should be considered in other emerging infections," said David Heymann, an infectious-disease researcher at the London School of Hygiene and Tropical Medicine.
Many scientists have long argued that CPT has been wrongly neglected, both as a therapy for emerging diseases and in preparation for future unknown threats.
CPT requires collecting survivors' blood, screening it for pathogens and then organising patient transfusion.
"Convalescent plasma is one of the few things you can get up and running quickly," said Calum Semple, a paediatrician and clinical virologist at the University of Liverpool, UK, who is involved in the Guinea Ebola trial.
According to the World Health Organisation (WHO), as of December 20, 19,340 people were infected with the deadly virus in Guinea, Liberia and Sierra Leone, and 7,518 of them had died.