Skin vaccinations may provide greater bioweapon protection

According to a paper published this week in the journal Nature, the most important aspect of the human immune system may be located in skin cells, making skin vaccination more effective than traditional muscle vaccination in the fight against bioweapons.

The smallpox vaccine, one of the most successful vaccines ever put into practice, used a scratch in the skin as opposed to the needles and syringes of today. The researchers involved in the study showed that immune cells called resident memory T cells provoke a much greater immune response in the skin, gut and lungs than the circulating memory T cells in the blood stream, the Scientist reports.

"In the past, people have conducted in vivo experiments that suggest resident memory and circulating memory cells confer comparable protection," Onur Boyman, an immunologist at the University of Zurich, said, according to the Scientist. "This paper provides a nice step forward in showing that these resident memory cells are indeed more effective against a skin infection as compared to central memory cells."

Thomas Kupper and Rachael Clark of Brigham and Women's Hospital in Boston pitted resident memory T cells against circulating memory T cells to determine which set provided a stronger protection against re-infection with a virus. The researchers tested the vaccinia virus, the core component of the smallpox vaccine, in mice.

"The resident memory cells won hands down," Kupper said, according to the Scientist. "It wasn't even a contest. They're much more effective. We're injured and infected through the skin many times during our lives, and we think this leads to the accumulation of populations of T cells that (spread) throughout our skin and stay there for long periods of time. It's a wake up call that we need to think about these T cells when we're making vaccines."

The findings may lead to an attempt to find new routes of vaccination through the skin. In addition, the study has implications for understanding immune diseases that are organ-specific like multiple sclerosis and asthma.