Therapeutic vaccines for mucosal cancers may work best when administered directly at the site of those tumors rather than at more conventional sites, such as the arm, researchers reported in Science Translational Medicine (2013;5:172ra20).
Most cancer vaccines are tested against subcutaneous tumors in preclinical models despite the fact that many human cancers are located at mucosal sites in the nose, mouth, and genital tract, explained the investigators. Because mucous membranes in these areas are equipped with powerful chemicals to keep out foreign invaders, the team theorized that harnessing these local mucosal immune systems with vaccines could be a way to fight cancers at mucosal sites, including head, neck, and genital cancers.
The researchers used a tip cone injector to administer vaccines through the noses of mice. Immunization route did in fact directly affect the vaccine’s efficacy in controlling mucosal tumors: The scientists found that head, neck, and lung cancer growth was inhibited when a therapeutic vaccine was delivered intranasally, but not when it was delivered intramuscularly.
Further examination revealed that this antitumor effect depended on the vaccine’s ability to activate and mobilize CD8+ T cells at the site of the tumor. Only intranasal vaccination elicited the necessary response from these cells.