CAMBRIDGE, Mass. — Good news for individuals who simply can’t stand to be stuck with a needle. Scientists from the Massachusetts Institute of Technology are developing an inhalable COVID-19 vaccine that could be even more effective than injectable ones. In fact, they believe their research also opens the door for preventing and treating cancers and other diseases.
The researchers hope that, like other vaccines administered to the throat, their development will spark an immune system response as soon as the infection is inhaled. Foundation research on mice shows that an inhalable vaccine is 25 times more effective that one injected into a muscle. That’s because sending the vaccine directly onto mucosal membranes — like those found in the mouth, nose, throat, and lungs — can get immune system cells, or T cells, to “set up shop” ready to attack an infection where it lands.
This COVID vaccine project began after scientists successfully tested an inhalable vaccine for the smallpox virus in mice. In the study, published in the journal Science Immunology, scientists aimed to develop an intratracheal (via the throat) vaccine for both viruses and cancer. Most vaccines are given as injections into muscle tissue. But most viral infections occur at mucosal surfaces.
There is an approved nasal vaccine for the flu, and an oral vaccine for typhoid. But both of those vaccines consist of live, weakened viruses, which are better able to cross mucosal barriers. For their experiment, researchers wanted to try peptide vaccines, made of proteins which mimic viruses, because they are safer and easier to produce.
But the downside of this type is that it is more difficult for them to cross the mucosal barrier and stay in the body.
To try to make peptide vaccines easier to deliver to the lungs, the researchers turned to attaching them to albumin proteins which are found in the bloodstream. A 2014 study by the same team shows this protein helps the peptides to accumulate in the lymph nodes, where they could activate a strong T cell response. In this latest research, scientists investigated whether albumin could also help peptide vaccines get across mucosal barriers such as those surrounding the lungs.
To test this idea, the researchers attached a string of fat molecules, which bind to albumin, to a peptide smallpox vaccine and delivered it to mice by the throat. The team found their vaccine was 25 times more effective than one administered to muscles.
They also showed that when mice were exposed to the smallpox virus months later, the intramuscular vaccine offered no protection, while all of the animals that received the vaccine intratracheally were protected.
“In this paper, we specifically focused on T cell responses that would be useful against viruses or cancer, and our idea was to use this protein, albumin, as sort of a Trojan horse to get the vaccine across the mucosal barrier,” says senior author Darrell Irvine in a statement. “These types of inhaled vaccines could also be used to treat cancer metastasizing to the lungs or even prevent cancer from developing in the first place. In both the virus and the tumor experiments, we’re leveraging this idea that, as other people have shown, these memory T cells set up shop in the lungs and are waiting right there at the barrier. As soon as a tumor cell shows up, or as soon as a virus infects the target cell, the T cells can immediately clear it.”
While Irvine is now turning his attention to a COVID vaccine, he says the method could be used to tackle HIV and influenza too.
SWNS writer William Janes contributed to this report.