A major breakthrough in the development of a highly effective vaccine against the deadly Nipah virus has been reported by a team of federal and university scientists. The results of their study, "A Hendra virus G glycoprotein subunit vaccine protects African green monkeys from Nipah virus challenge," will appear in Science Translational Medicine online.
The research team members are a collaborative group of investigators from the Uniformed Services University of the Health Sciences (USU), Bethesda, Md.; the University of Texas Medical Branch (UTMB) and Galveston National Laboratory (GNL); the National Institutes of Health (NIH)'s National Institute of Allergy and Infectious Diseases (NIAID) and Rocky Mountain Laboratories (RML); and the Boston University School of Medicine and National Emerging Infectious Diseases Laboratories Institute (NEIDL).
Nipah virus and Hendra virus emerged in the 1990s causing serious disease outbreaks in humans and livestock in Australia, Malaysia, Singapore, Bangladesh and India. Recent Nipah outbreaks have resulted in acute respiratory distress syndrome and encephalitis, person-to-person transmission, and greater than 75 percent case fatality rates among humans. The viruses are found naturally in several species of Pteropid fruit bats (flying foxes). The NIH and Centers for Disease Control and Prevention have classified Nipah and Hendra as biothreat agents, and the U.S. Department of Agriculture has characterized them as agriculture threat agents. In fact, the infectious agent of last year's cinematic release "Contagion" was modeled after Nipah virus.
In experiments carried out in African green monkeys at the RML in Hamilton, Mont., where there is a high-level safety and security facility for working with live Nipah virus, the team of researchers, under the direction of Heinz Feldmann, MD, PhD, chief of the RML, Laboratory of Virology, demonstrated that immunizing monkeys with a vaccine based on the Hendra virus attachment G glycoprotein afforded complete protection against Nipah virus infection with no evidence of disease.
These findings are really quite promising and appear to offer a real potential treatment for Hendra virus infection in people, says Christopher C. Broder, PhD, professor of Microbiology at USU and study corresponding author.
The vaccine is a soluble portion of the G glycoprotein of Hendra virus, known as Hendra-sG, which mediates viral infection and is produced in the laboratory using molecular techniques. Lead author, Katharine Bossart, PhD, a USU alumna and assistant professor in the Department of Microbiology, Boston University School of Medicine, developed the Hendra-sG vaccine while a student in Broders laboratory at USU. Since the vaccine is only a recombinant piece of the virus, it can be produced by itself and purified, and is a type of vaccine known as a subunit, thus making it extremely safe to use, Bossart says.
According to study co-author Thomas W. Geisbert, PhD, professor in the Department of Microbiology and Immunology at UTMB and GNL, This work now provides key evidence that a simple and safe recombinant vaccine against Nipah virus is possible. Demonstrating this in a nonhuman primate model is a major step forward in developing it for future therapeutic use in people.
There are currently no approved vaccines for prevention of infection and disease caused by Nipah and Hendra for use people or livestock, Broder says. This Hendra-sG vaccine has now been shown to be fully effective against infection by both Nipah and Hendra virus in at least three animal species, demonstrating its potential as a safe and effective vaccine as a possible livestock vaccine and now also as possible vaccine for use in people.