PHILADELPHIA, Pa. — The next time someone offers you a stick of gum, it may have nothing to do with your breath and everything to do with COVID-19. University of Pennsylvania researchers have created a chewing gum laced with a plant-grown protein capable of “trapping” and neutralizing SARS-CoV-2, the virus causing COVID. They report the gum can lower viral load in saliva and potentially reduce transmission rates.
“SARS-CoV-2 replicates in the salivary glands, and we know that when someone who is infected sneezes, coughs, or speaks some of that virus can be expelled and reach others,” says study leader Henry Daniell of Penn’s School of Dental Medicine in a university release. “This gum offers an opportunity to neutralize the virus in the saliva, giving us a simple way to possibly cut down on a source of disease transmission.”
Vaccination efforts have greatly helped in the fight against COVID-19, but even fully vaccinated individuals can still become infected. Moreover, recent research even suggests viral loads found in the saliva of vaccinated people are quite similar to the unvaccinated.
Repurposing medicated gums for the pandemic
Long before COVID-19 emerged in 2020, Daniell had already been analyzing the ACE2 (angiotensin-converting enzyme 2) protein for hypertension research purposes. ACE2 is what COVID seeks out on the surface of cells, attaching itself using the virus’s spike protein.
Via a patented plant-based production system, Daniell and his team grew the ACE2 protein within a lab setting. To do this, they “bombarded” plant material with protein DNA, causing plant chloroplasts to take up the DNA and begin growing the protein.
This plant material, which the team then freeze-dries and grinds up, is a viable means of protein delivery according to the study. The new protein production system is also attractive because it avoids many of the time-consuming and expensive aspects of traditional protein drug synthesis processes.
All of that prior ACE2 protein research put Daniell in a unique research position once COVID-19 arrived. Importantly, prior coronavirus research has shown that ACE2 injections have the capacity to reduce viral load among people with severe COVID-19 infections.
Additionally, Daniell also worked on a separate project involving the creation of a new chewing gum infused with plant-grown proteins, capable of fighting dental plaque. Daniell pondered if a gum infused with plant-grown ACE2 proteins could work to impede SARS-CoV-2 viral activity in the mouth.
Blocking COVID from hijacking the cells
He brought his idea to Ronald Collman of Penn Medicine, a virologist and pulmonary and critical care doctor. Dr. Collman has been collecting various samples (blood, nasal swabs, and saliva) from COVID-19 patients for research purposes.
“Henry contacted me and asked if we had samples to test his approach, what kind of samples would be appropriate to test, and whether we could internally validate the level of SARS-CoV-2 virus in the saliva samples,” Dr. Collman states. “That led to a cross-school collaboration building on our microbiome studies.”
As a test, the team grew ACE2 in some plants and then combined it with another compound enabling ACE2 to cross stomach barriers and bind. Researchers turned that plant material into cinnamon-flavored gum tablets. After giving COVID-19 patients some of this gum, the team collected nasopharyngeal swabs which confirmed that the new gum could neutralize coronavirus.
Further tests conducted on less pathogenic viruses that scientists modified to express the SARS-CoV-2 spike protein showed that this new type of gum is capable of “largely preventing” viruses or viral particles from entering cells. This blockage occurs in two ways: either by protecting the ACE2 receptor on the cells altogether, or by directly binding to the spike protein.
Creating an ‘inexpensive’ way to end the pandemic
A third round of testing saw researchers expose saliva samples from COVID-19 patients to the ACE2 gum. Sure enough, viral RNA levels within the samples dropped to near undetectable levels.
“Henry’s approach of making the proteins in plants and using them orally is inexpensive, hopefully scalable; it really is clever,” Dr. Collman adds.
“We are already using masks and other physical barriers to reduce the chance of transmission,” Daniell concludes. “This gum could be used as an additional tool in that fight.”
Moving forward, study authors are already working on gaining approval for a clinical trial. While these findings are preliminary, and more research is necessary, the research team says if the gum is safe and effective it could be an invaluable COVID-19 asset in the race to end this pandemic.
The study is published in the journal Molecular Therapy.