Creating a vaccine for an ancient, all-too-current disease

May 09, 2024

“My whole mission in life is to help,” says Caroline Cameron. “Especially people whose voices don’t always get heard.”

The UVic microbiology professor has spent her career doing exactly that. From her post-doctoral research onward — almost 30 years now — Cameron has been studying syphilis. People have known about the disease and its devastating effects for hundreds of years, and yet today social and societal changes are leading to a steep increase in global rates of infection. Lack of knowledge that the disease is still a problem and ongoing stigma prevent people from getting tested. So although syphilis is still treatable with antibiotics, a vaccine is key to help reduce the enormous personal, social and economic costs of this ancient disease.

Cameron’s research program has been supported by the US National Institutes of Health (NIH) since 2002. Now the National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH, is providing Cameron’s research with additional support, this time with a five-year $7.8 million USD grant for “Development of a Chimeric Syphilis Vaccine Candidate to Combat Local, Disseminated and Congenital Syphilis Infection.”

Scientists have studied syphilis almost from the first appearance of the disease in Europe. Although the bacterium behind it, the spirochete Treponema pallidum, was identified in 1905, very few people anywhere have studied the organism itself in depth. In fact, Cameron’s team is the only one in Canada. In part that’s because growth of the bacterium is complicated. An “obligate human pathogen,” T. pallidum must be in contact with human cells in order to survive.

Because T. pallidum requires contact with human cells to grow, Cameron’s focus on vaccine targets has kept her eyes on the surface of the spiral-shaped bacterium, where proteins are inserted into the cell membrane.

“We know it’s not going to be one protein that’s the magic target,” she says. “It’ll be more than one.”

However, making a protein-based vaccine is expensive and complicated, so industry partners want fewer rather than more proteins to target when creating a vaccine to control the rampant increase of cases around the world.  That led Cameron and her research partners at the University of Washington and Duke University to consider creating a new polypeptide with characteristics of several existing proteins. While UVic is the lead institution and Cameron is the lead principal investigator, the team also includes co-PI Lorenzo Giacani of the University of Washington and a diverse team of about 20 others at all career stages and from both academia and industry. Co-investigator and UVic biochemist Martin Boulanger will engineer a single gene from pieces of multiple genes that encode for sections of different proteins. The result will be a single protein with hybrid functions—the chimera.

The ancient Greeks described Chimera as a hybrid monster with the head of a lion, a fire-breathing goat head emerging from its back and a serpent at the hind end. Cameron and her team’s modern, molecular approach is smaller in scale, but perhaps will be just as devastating to the tiny spiral pathogen that has caused so much anguish over so many centuries.

Research reported in this publication will be supported by the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, under Award Number U01AI182035. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

 

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