In addition to protecting against pathogens that infect the lungs, 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, the researchers say.
The researchers also tested a mucosal vaccine against cancer. In that case, they used a peptide found on melanoma cells to immunize mice. When the vaccinated mice were exposed to metastatic melanoma cells, T cells in the lungs were able to eliminate them. The researchers also showed that the vaccine could help to shrink existing lung tumors.
This kind of local response could make it possible to develop vaccines that would prevent tumors from forming in specific organs, by targeting antigens commonly found on tumor cells.
“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,” Irvine says.
This strategy could also be useful for creating mucosal vaccines against other viruses such as HIV, influenza, or SAR-CoV-2, Irvine says. His lab is now using the same approach to create a vaccine that provokes a strong antibody response in the lungs, using SARS-CoV-2 as a target.