US-based Brigham and Women's Hospital is set to begin the first-ever clinical trial to test the safety and efficacy of a nasal vaccine aimed at preventing and slowing down the progression of Alzheimer's disease (AD).

The vaccine uses the immune modulator Protollin, an investigational intranasal agent that stimulates the immune system. Protollin is composed of proteins derived from bacteria and has been used safely in humans as an adjuvant for other vaccines.

"The immune system plays a very important role in all neurologic diseases," said Howard L. Weiner, MD, co-director of the Ann Romney Center for Neurologic Diseases at the Brigham, in a statement. "For 20 years, there has been growing evidence that the immune system plays a key role in eliminating beta-amyloid. This vaccine harnesses a novel arm of the immune system to treat AD," added Tanuja Chitnis, Professor of Neurology at the Brigham.

Protollin is designed to activate white blood cells found in the lymph nodes on the sides and back of the neck to migrate to the brain and trigger clearance of beta-amyloid plaques -- one of the hallmarks of AD. The clinical trial will include 16 participants, between 60 and 85 years of age with early, symptomatic AD. The participants will receive two doses of the nasal vaccine one week apart.

If the trials prove the safety of the vaccine it "could represent a non-toxic treatment for people with Alzheimer's, and it could also be given early to help prevent Alzheimer's in people at risk", Weiner said.

The phase I trial's primary objective will be to determine the safety and tolerability of the nasal vaccine. The research team will also measure the effect of nasal Protollin on participants' immune response, including its effects on white blood cells, by examining cell surface markers, gene profiles, and functional assays.

The trial also marks the culmination of 20 years of research at the hospital, the statement said. "The launch of the first human trial of a nasal vaccine for Alzheimer's is a remarkable milestone...it's exciting that after 20 years of preclinical work, we can finally take a key step forward toward clinical translation and conduct this landmark first human trial," Weiner said.