Though needles are used for many medical procedures, including vaccination, generally, no one likes them being pushed into one of your muscles. Have you ever wondered about a vaccine that is a cream? Even better, it is a pain-free cream vaccine not followed by fever, swelling, or a sore arm.
Researchers at Stanford University have domesticated Staphylococcus epidermidis, a harmless skin-colonizing bacteria, that could bring this vision into reality.
“We all hate needles – everybody does. I haven’t found a single person who doesn’t like the idea that it’s possible to replace a shot with a cream,” Michael Fischbach.
With its dryness and way too salty for most single-celled creatures, the skin makes a terrible place to live in. Still, some of the hardy microbes like Staphylococcus Epidermidis. These microbes reside on every hair follicle.
Previously, immunologists neglected skin-colonizing bacteria, because they don’t seem to contribute much to our well-being. However, the assumption turns out to be incorrect, and the immune system mounts a much more aggressive response against S. epidermidis than anyone expected.
Standford researchers were keen to test how the immune system mounts on the skin with no S. epidermidis if it were to turn up there. To test, researchers introduced this microorganism on the head of a mouse.
After six weeks, the mouse’s blood was tested to check if the immune system produced antibodies that bind to S. epidermidis. Researchers were shocked to see the amount of antibodies formed, whose concentration was even more significant than a regular vaccine.
Fischbach says, “Those antibodies’ levels increased slowly, then some more – and then even more. It’s as if the mice had been vaccinated.“
Unbelievable: Skin creams aren’t what we thought they were
Researchers found that the immune response to S. epidermidis happens preemptively before any problem. Continuing their experiment, researchers identified the protein Aap responsible for tripping off a powerful immune response.
Aap is a treelike structure, five times the size of an average protein. Since the protein has been identified, researchers have been looking forward to putting it to work.
Researchers continued to apply S. epidermidis to the mouse, but this time using bioengineered S. epidermidis encoding the tetanus toxin fragment. The mouse on the toxin displayed extremely high antibodies targeting the tetanus toxin.
The team found that the procedure works in mice. Next, the lead author, Yasmine Belkaid, will be experimenting on monkeys. If everything runs as planned, the team expects to enter clinical trials within two or three years.
“Our species’ virtually 100% skin colonization by S. epidermidis should pose no problem to the construct’s use in people,” says Fischbach.
“We think this will work for viruses, bacteria, fungi, and one-celled parasites. Most vaccines have ingredients that stimulate an inflammatory response and make you feel a little sick. These bugs don’t do that. We expect that you wouldn’t experience any inflammation at all.”
Journal Reference
- Bousbaine, D., Bauman, K.D., Chen, Y.E. et al. Discovery and engineering of the antibody response to a prominent skin commensal. Nature (2024). DOI: 10.1038/s41586-024-08489-4
