Skin vaccines may be on the horizon
August 31, 1999
Web posted at: 11:48 AM EDT (1548 GMT)
By Rochelle Jones
(WebMD) -- As school starts and kindergartners cringe at the sight of yet another vaccination needle, parents may be dreaming of a quicker and easier way to keep their children safe from childhood diseases.
Fortunately, ouchless vaccines may now be more than a fantasy -- although certainly not yet a reality. In this week's Nature Biotechnology journal, researchers at Stanford University School of Medicine report that they successfully immunized mice against diseases such as hepatitis B by using a skin vaccine.
With the vaccine applied simply by using a swab, the study could mean that people might be vaccinated more easily someday, said Hongran Fan, lead author of the article and clinical researcher at Stanford.
"In the future, people ... could wear just a very small skin patch and receive an entire cocktail of vaccines," Fan said.
Unlike traditional vaccines, which mobilize the body's defense system by injecting a weak version of the disease-causing virus, the Stanford researchers used a more direct approach. They pared the virus down to its essential DNA. They then mixed the DNA into a watery solution, which they wiped on the mice's skin. The researchers found that the mice produced immune responses to the viruses as if they had been injected with a conventional vaccine.
Although other scientists have experimented with DNA vaccines, the Stanford team is the first to successfully demonstrate the skin vaccines' effectiveness in mice without using needles. Hair follicles on the skin act as shunts to bring the vaccine from the skin into the body. Mice that lacked normal hair follicles didn't develop the same immune response.
Stephen Johnston, professor of biochemistry at the University of Texas Southwestern Medical Center and a pioneer in the field of DNA vaccines, said skin vaccines have the potential for making vaccines both easier to produce and cheaper.
In the early 1990s, Johnston developed a well-publicized "gene gun" that shot tiny pellets of DNA directly into the cells of animals, provoking an immune response. The Stanford research brings another angle to the delivery of DNA vaccines -- the use of hair follicles.
"The punch line here is that we've probably been delivering vaccines to the wrong place -- the muscle -- for a long time," Johnston said.
So far no DNA vaccines are on the market. However, the American Society for Microbiology reported last year that "promising" DNA vaccines that could be applied to skin are currently being developed for more than 15 illnesses, including AIDS, herpes, tuberculosis, malaria and rotavirus, a common cause of childhood diarrhea.
DNA vaccines have advantages that go far beyond the ouchless response, Fan said. They are cheaper to produce and, unlike conventional vaccines, don't require cold storage, a real advantage in developing countries where vaccines are often most needed.
"It could revolutionize immunizations," she said. "We can vaccinate the whole population very cheaply and very conveniently."
Copyright 1999 WebMD, Inc. All rights reserved.
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