A faster response

H1N1 flu vaccine

Emory began clinical trials of an H1N1 flu vaccine in August as one of eight NIH vaccine and treatment evaluation units. The trials tested both safety and efficacy and were critical in preparing for this fall’s vaccination program.

Currently flu vaccines must be grown in chicken eggs, extracted, and then mass-produced.

The process can take months when large supplies are demanded. However, at Emory, a team of scientists, led by microbiologist and immunologist Richard Compans, is working to rapidly speed up manufacturing of a flu vaccine.

How are they doing it? They are using virus-like particles (VLPs), empty shells that look like viruses but lack the ability to reproduce. VLPs are man-made decoys of natural viruses that prompt the immune system to fend off infection when exposed to the real thing.

While VLPs copy the structure of authentic viruses, they are not infectious, making them safer to produce than vaccines that use live, but weakened, organisms. When a person is exposed to the live virus, the immune system releases antibodies to protect against infection. That also happens with VLPs. They are recognized by the immune system as the "real" virus upon immunization, causing the body to produce antibodies, but not causing illness.

In laboratory testing with mice, supported by the CDC and the Georgia Research Alliance, the Emory team has shown that a VLP vaccine could significantly cut the production time needed to manufacture the vaccine. Vaccines grown conventionally typically take up to six months to get to market. Not so with VLPs, says Emory microbiologist Sang-Moo Kang, who has been refining the VLP approach for eight years.

"After identifying the genes to constructing and making the VLPs, we can start to produce vaccines in four to six weeks," says Kang.

Another positive: The Emory researchers also found that immunity from the VLP vaccine in mice wore off more slowly than that induced by conventional flu vaccines in humans. "In a mouse, two years is the average lifespan," says Kang. "We have confirmed that the VLP immune system in mice can last 18 to 20 months. So this protective immunity is maintained throughout their lifetime." —Dana Goldman

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