Bacteria, plants could help modernize flu shots
Tue Apr 11, 2006 2:53 PM ET
CLEVELAND, April 11 (Reuters) - Turning bacteria, plants or insect cells into protein factories could be a key to faster vaccine production to fight a flu pandemic or another outbreak, vaccine developers and U.S. scientists said on Tuesday.
Those technologies and other new approaches might not reach the market for years -- if ever -- and could be too late if a feared avian flu pandemic erupted in the near future, officials said. But the prospect of a bird flu crisis has prompted new interest in finding alternatives to the unwieldy, egg-based system that takes months to turn out flu vaccine.
"We're understanding what we need to know and what the technical questions we need to ask next are. There is a driving need to speed these processes along," Dr. Michael Callahan, an infectious diseases expert at Massachusetts General Hospital, told a meeting called to generate new ideas for making immunizations to fight a pandemic virus.
Vaccines are considered a key defense should the H5N1 avian flu virus that has spread among birds in Asia, Europe and parts of Africa evolve into a form easily transmitted among people, sparking a pandemic.
Several companies are focusing on new vehicles for growing antigens -- the bits of a virus or bacterium needed to spur a person's immune system to fight an infection.
VaxInnate, a New Jersey-based biotechnology company, reported success using E. coli bacteria, which can cause a sometimes-fatal infection but also can be used to grow vaccine ingredients when the harmful part of the bacterium is removed.
"You can make a boatload of this stuff. It's easy," VaxInnate President and Chief Executive Alan Shaw said at the meeting, held at Case Western Reserve University and sponsored by the National Academy of Engineering and the Institute of Medicine.
Dowpharma, a unit of Dow Chemical Co., has been using different bacteria found in soil and water, P. fluorescens, which may make a higher volume of antigens more quickly than E. coli, said Lada Rasochova, the company's research and development group leader for vaccines.
Any method using bacteria could be challenging, Callahan said. Bacteria can churn out proteins quickly, but they can be unpredictable, he said. "They may not faithfully produce vaccine," he said.
Other companies are trying to make antigens in cells taken from insects and reproduced in a lab, or in plants, Callahan said. People could eat the plants, or the proteins they produce could be extracted and put into vaccines.
A more near-term option is growing influenza vaccine in cell cultures, a method large vaccine makers are working on. Some experts said that approach would be unlikely to cut production times significantly, although it would eliminate some of the difficulties with obtaining and handling chicken eggs.
Also, some viral strains do not grow well in chicken eggs.
In addition to improving production, companies are searching for ways to speed the testing of new vaccines. Orlando, Florida-based VaxDesign has developed an "artificial immune system" using human cells and collagen in a lab dish to test whether a potential vaccine is likely to work in people, Chief Executive William Warren said.
Most ideas presented at the meeting were still in animal or lab tests or early human studies. Experts expect egg-produced vaccines to continue being made for years, if not decades.
"They will certainly continue to be the backbone for some time to come," Callahan said.
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