Could Alzheimer's be prevented with a vaccine?

Scientists have devised a vaccine that has shown promise in the treatment of psoriasis and cat allergies, as well as in the prevention of Alzheimer's disease. 

The new research was a collaborative effort among universities in the United Kingdom and Switzerland, and the findings were published in the journal Nature Vaccines.

Dr. John Foerster, a dermatologist and clinical senior lecturer at the University of Dundee in Scotland, U.K., jointly supervised the research with Martin Bachmann, a professor of vaccinology at the Jenner Institute in Oxford, U.K.

Dr. Foerster, Prof. Bachmann, and their research team designed a new vaccine by combining an existing anti-tetanus vaccine with a protein from a virus that affects a variety of plants.

The viral protein was taken from the so-called cucumber mosaic virus (CMV) — a virus that received this name because it was first found in cucumbers. 

The scientists incorporated a so-called tetanus-epitope into the CMV particles and tested the resulting vaccine in animal models of psoriasis, allergies, and Alzheimer's disease.

An epitope is the part of a foreign substance — in this case, tetanus — that elicits an immune response in the body.

Vaccine effective for chronic conditions

As the researchers explain, the vaccine was successful against psoriasis and cat allergies, with the mice showing signs that their immune system was fighting off the infection.

The vaccine proved to be efficient even in old mice and at low doses.

Dr. Foerster explains the mechanism by which his discovery could prevent chronic diseases or treat them after they have already developed. "The idea is pretty simple. [For] diseases such as psoriasis or eczema, the newest and most effective medicines on the market are so-called 'antibodies,' which are what you and I produce against bugs in a common cold."

"For chronic diseases," he adds, "these antibodies are specially made against one of the body's own proteins. By blocking that single protein, the disease gets better." 

"To use the example of psoriasis," he continues, "a protein called Interleukin 17 needs to be active for the disease to progress." As the authors explain in the study, existing drugs that target this protein are very expensive, although efficient and safe.

"By creating a vaccine that stimulates the body to make antibodies against Interleukin 17 itself," explains Dr. Foerster, "we can replace the need for frequent and expensive injections."

"[We can] make this type of treatment much more affordable and accessible to patients who could otherwise not afford specially made antibodies," he notes.

"Our research shows that this technique works in mice and, importantly, our new vaccine technology shows that it is likely to be a more effective type of vaccine than existing ones in older people." 

Dr. John Foerster

"Since many patients with chronic conditions like psoriasis are elderly," he continues, "this technology may work much better."

A vaccine against Alzheimer's

In a mouse model of Alzheimer's disease, the vaccine increased levels of certain antibodies that are believed to protect against the neurodegenerative disease. 

More specifically, the vaccine raised levels of the Immunoglobulin G antibodies that are thought to recognize and fight against aggregates of beta-amyloid plaque in the brain — which is a marker of Alzheimer's disease.

Based on the findings, the authors suggest that "a prophylactic vaccination approach could be a viable public health intervention" against Alzheimer's disease. 

Evidently, more research is needed to test these benefits in humans. The vaccine could be adapted to almost any foreign substance, or antigen, the authors write, and it would be "ideally suited [...] for aging populations."

This is what makes the findings particularly encouraging, says Prof. Bachmann. He notes:

"Alzheimer's disease usually develops in elderly people. The fact that the vaccine described here is optimized for old individuals seems therefore particularly helpful."

"An additional important aspect," Prof. Bachmann concludes, "is that we developed a platform technology and are currently broadening our preclinical studies to vaccines against Parkinson's disease as well as chronic pain."