How Praetorian Bio Is Building Vaccines Against Tooth Decay
Supporting Preventive Vaccines for Oral Health
Alireza Masrour
Developing Intranasal Vaccines Against The Two Most Common Oral Diseases
Praetorian Bio, based in the San Francisco Bay Area, develops intranasal vaccines against tooth decay and gum disease. Both conditions affect billions of people, and no approved vaccine exists for either.
Both programs run on one platform. It combines AI-guided antigen design with outer membrane vesicle (OMV) technology, already used in an approved meningococcal B vaccine, and delivers the vaccine intranasally to build immunity at the sites where these bacteria live.
The lead program, CaviStop, is being developed as a voluntary, preventive vaccine against tooth decay, given at dental visits or pharmacies. It targets the bacteria that cause caries, led by Streptococcus mutans. In preclinical studies presented at IADR 2026, serum from vaccinated animals reduced biofilm formation by more than half in laboratory tests, and CaviStop-induced antibodies recognized both main caries-causing species. The second program, GingiVax, targets Porphyromonas gingivalis, a key driver of gum disease in adults. Praetorian Bio protects both programs with its own US patent filings, and CaviStop also has an international PCT application.
Praetorian Bio has raised approximately $1.5M to date from Gorges Ventures, Braumigan Capital, Archer Insights, and Plug and Play.
Why Is This Problem Significant, & How Large Is Its Impact?
Oral disease is the most widespread health problem in the world. The WHO estimates that untreated tooth decay affects about 2.5 billion people and severe gum disease affects more than 1 billion. Cases of oral disease have grown by about a billion worldwide over the last 30 years. Treatment is costly, and patients pay for most of it out of pocket.
Today's tools include brushing, fluoride, sealants, cleanings, and fillings. All of them depend on daily habits and regular access to a dentist, and the global burden continues to rise. Both diseases are caused by specific bacteria, making them suitable for vaccination. A voluntary, preventive vaccine that trains the immune system to keep those bacteria in check is designed to stop disease at its source.
Gum disease raises the stakes beyond the mouth. Gum disease is a leading cause of tooth loss in adults, and observational studies have linked it to cardiovascular disease, diabetes, and Alzheimer's disease. That makes Porphyromonas gingivalis a target worth going after. For families, decay means pain, infections, and a lifetime of fillings, root canals, and extractions. A vaccine administered at dental visits or pharmacies could shift care from repair to prevention.
Meet the Team Behind Praetorian Bio
Armando Cuesta, MD, MBA, Co-Founder & CEO. Armando is a physician and biotech fund manager with a Cornell MBA and more than 10 years of investing across public and private biotech markets. He co-founded and managed a $50M listed biotech fund and founded Korion Life Sciences, a regulated European life sciences fund-of-funds.
Francisco León, MD, PhD, Co-Founder, President & Chairman. Francisco co-founded Provention Bio and served as its Chief Scientific Officer. Under his leadership, TZIELD became the first therapy approved to delay the onset of type 1 diabetes, and Sanofi acquired Provention Bio for $2.9B. He also co-founded Celimmune, which Amgen acquired, and was the founding Head of Translational Medicine at Janssen. He has participated in or led the development of six marketed drugs, with around 90 publications and 21 patents.
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Co-Founder & CEO
“Tooth decay is the most common disease on earth, and humanity treats it as a fact of life. It is not. It is a bacterial infection, and infections can be vaccinated against. Our moonshot is a world where no one needs a filling and no one loses their teeth to gum disease. With Plug and Play behind us, we are taking CaviStop toward the clinic to make that future real.”
Why We’re Excited to Invest
We met Praetorian Bio at the Plug and Play and Cornell virtual pitch session on July 1, 2026, and our investment team met the founders in August. We invested in September 2026.
The platform applies proven technology to a new target. OMV technology is already in an approved meningococcal B vaccine, and Praetorian Bio pairs it with AI-guided antigen design and intranasal delivery. That combination lets one platform drive two programs, CaviStop and GingiVax, against diseases for which there are no approved vaccines.
The team carries the experience this program needs. Francisco León took Provention Bio from founding to a $2.9B acquisition, Alicia Solórzano moved vaccines from discovery into the clinic for 20 years, and Dinja Oosterhoff and Ivo Ploemen secured more than $20M at Intravacc to take vaccines to first-in-human trials. Armando Cuesta brings more than 10 years of biotech investing.
The early data and the go-to-market path gave us conviction. Antibodies induced by CaviStop recognized both main caries-causing species, serum from vaccinated animals cut biofilm formation by more than half, and both programs have their own patent filings. A voluntary vaccine given at a dental visit or at a pharmacy uses existing care channels.
Plug and Play is one of the most active VCs globally. Our goal is to fund the teams building the defensible businesses of the future. Join our ecosystem today.
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