MONDAY, SEPTEMBER 26, 2016

Sugar polymer may be key to broad-spectrum vaccine development

Researchers from Brigham and Women's Hospital recently discovered a sugar polymer common on the cell surface of many pathogens may be a promising target in the development of a broad-spectrum vaccine.

The study, which was published this week in Proceedings of the National Academy of Sciences, reports the sugar, also known as beta-1-6-poly-N-acetyl glucosamine or PNAG, is made by a number of bacterial, fungal and other microbial organisms that can cause disease.

The researchers said the immune system does not usually target PNAG because it is ineffective at killing the microbes. Thus, researchers created vaccine-induced synthetic antibodies to respond to PNAG and tested it in human-derived antibodies and in mice.

The human-derived antibodies were able to bind with both natural and synthetic forms of PNAG and killed the microbes producing it. In the trials with mice, mice became protected from a number of pathogens, including those which cause strep throat, pneumonia, fatal food poisoning, meningitis, fungal infections and the most serious form of human malaria, cerebral malaria.

Researchers detected PNAG present on the microbial surfaces of other pathogens which cause gonorrhea, trichomoniasis, typhoid fever and serious gastrointestinal infections.

"The possibility to use one agent to target so many different organisms including gonorrhea, TB and malaria is very exciting and unprecedented so far in the field of infectious diseases," Gerald Pier, the senior study author, said. "However, whether or not one vaccine will work for any of these organisms, let alone many of them, will only be known once the vaccines and antibodies are thoroughly tested in humans."

Phase I of the study has already been conducted and the antibody was found to be safe. Human clinic trials with a PNAG-based vaccine are expected to begin in 2014.