New Delhi, June 6: Indian scientists have developed tiny spheres loaded with viral protein segments that show promise as a candidate oral vaccine against the hepatitis-B virus that may eliminate the need for injections and booster doses.
The researchers at the All India Institute of Medical Sciences (AIIMS), New Delhi, have through studies on mice shown that a single oral dose of the nano-size spheres called nanoparticles can stimulate the immune system into protecting the body from the hepatitis-B virus for over eight weeks in the animals.
"Eight weeks in mice may be roughly equivalent to eight years in humans," said Amit Dinda, professor of pathology at the AIIMS who led the research funded by the Union science and technology ministry's department of biotechnology. "Present-day vaccines against hepatitis-B virus are injectible vaccines and require two boosters after one and six months."
While the new concept has yet to be demonstrated in humans, Dinda and his colleagues believe their nanoparticle has some unique features that make it an attractive candidate as an oral vaccine delivery system.
The researchers have published their findings in the journal Vaccine.
The AIIMS scientists fabricated the nanoparticles combining a polymer material called polycaprolactone with a detergent-like substance called a surfactant and used them as couriers to transport protein segments of the hepatitis-B virus into the body.
Their laboratory studies showed that the nanoparticles ingested by the mice are absorbed through the intestinal walls into the lymphatic system via a set of cells called macrophages which in turn alert other arms of the immune system to generate a protective response against the hepatitis-B virus.
"This is a unique property of these nanoparticles - they continue to stimulate the immune system for periods much longer than most other experimental systems tested," Dinda said. "We're hoping this nanoparticle technology will emerge a candidate for safe and oral delivery of vaccine which will be helpful for mass vaccination campaigns."
The hepatitis-B virus, which is mainly contracted through contaminated needles or transfusions, can in some patients cause severe and chronic infections that can sometimes progress to liver cancer.
Over the past decade, several researchers elsewhere in the world proposed similar oral vaccines for hepatitis-B. One even proposed banana laced with viral proteins as an edible vaccine. But none has panned out into commercial vaccine.
"We think it's the combination of the surfactant and polymer that makes this nanoparticle attractive as a vaccine," Dinda said.
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发表于 2016-6-7 10:13
