Growing immunity: These images show insect cells growing without virus genes (top) and with virus genes (bottom). Scientists say the approach can produce 100,000 doses of vaccine per week, and can be adapted for different viruses, including H1N1 (swine flu).
Protein Sciences
The FDA wants further evidence that the novel approach is completely safe.
A new method of making flu vaccines is faster, more efficient, and more robust than the one that has been in use for the last 50 years. It has the potential to scale up rapidly, to deal with new strains of influenza such as this year's H1N1, and to help stem a pandemic tide. However, a U.S. Food and Drug Administration advisory panel voted in late November not to approve the technology, which involves growing key vaccine ingredients inside caterpillar cells instead of in chicken eggs, as is currently done. The FDA says that the company behind the new approach, Protein Sciences, based in Meriden, CT, needs to test it further before the method can be approved for use in the United States.
Jose Romero, chief of pediatric disease at Arkansas Children's Hospital and a member of the 11-person FDA panel, says that, while the company has more to do in order to prove safety, the cell-based technology shows considerable promise.
"This type of technology is going to move traditional influenza vaccinology into the 21st century," says Romero. "We recognize that there may come a day when a strain does arrive that cannot be supported by growth in traditional egg-based technology, and this and other cell-based technologies can breach that problem and provide us with another avenue for developing vaccines."
Today's egg-based vaccine technology is slow and unwieldy, requiring at least six months' of production time and millions of eggs to supply enough doses for a regular flu season. If a new virus appears unexpectedly, the antiquated system wouldn't be able to gear up fast enough to produce a new vaccine, many experts agree. What's more, if the virus itself were derived from birds, it might reduce the supply of eggs, hampering the country's main means of vaccine production.
For the past decade, Protein Sciences, along with a number of other companies, has been looking to cell-based vaccines as a more efficient and robust alternative. Instead of growing viruses in chicken eggs, researchers inject virus strains into insect cells. Both the virus and the cells then grow and multiply quickly in bioreactors. Scientists break the cell walls and harvest a key protein, called hemagglutinin, produced by the virus. This protein, found on the influenza virus's outer surface, is responsible for binding to cells in the body, causing a viral infection. Scientists purify and inactivate the harvested protein so that it can stimulate an immune response without causing an infection. The protein is the main ingredient in a vaccine.
Protein Sciences' technology, which is twice as fast as the egg-based approach, is a slight variation on the conventional cell-based approach. Instead of growing live viruses, the company replicates viral DNA within cells. The genes for hemagglutinin are extracted from a dead flu virus and injected into baculovirus--a virus that infects a caterpillar called the armyworm. The baculovirus is then injected into ovary cells isolated from the armyworm. In a bioreactor, the virus eats away at cells, replicating DNA and producing hemagglutinin.
With H1N1 vaccine supplies delayed, attention turns to faster-to-make "virus-like particles."
As new influenza strains emerge, researchers struggle to speed vaccine development.
A company is preparing human trials of a DNA-based, universal influenza vaccine.
Any status on vaccines from tobacco plant cells? How does this plant-based method compare with animal or insect methods?
Here a news release from Medicago about that:
Medicago begins human clinical testing with its avian flu pandemic vaccine
10/01/2009
QUEBEC CITY, Oct. 1 /CNW/ - Medicago Inc. (TSX-V: MDG) a biotechnology company focused on developing highly effective and affordable vaccines based on proprietary manufacturing technologies and Virus-Like Particles (VLPs), today announced that it has initiated a Phase I human clinical trial with its H5N1 Avian Influenza vaccine ("H5N1 vaccine"). Enrolment is ongoing and vaccination has commenced. The Phase I placebo-controlled, double-blind, dose-escalating study will evaluate safety, tolerability and the immune response of the Company's H5N1 vaccine candidate in 48 healthy volunteers between the ages 18 to 60. Results of this study are expected during the fourth quarter of 2009.
"This first human study with our lead vaccine candidate confirms Medicago's development as a clinical stage company," said Louis P. Vézina, Chief Scientific Officer of Medicago. "This is an important step for our H5N1 vaccine candidate, which has the potential to be highly effective, cross-protective, less expensive and faster to produce than current influenza vaccines."
About Medicago's pandemic flu vaccine candidate
Medicago's H5N1 vaccine candidate was formulated to protect against the avian influenza virus. It is manufactured in Nicotiana benthamiana, a relative of the tobacco plant, using the Company's proprietary VLP technology. VLPs have several advantages over traditional influenza vaccines. They resemble the virus, allowing them to be recognized readily by the body's immune system, however, they lack the core genetic material making them non-infectious and unable to replicate. Medicago's VLP-based vaccine has shown in preclinical studies it can provide cross- protection against different strains of avian flu, such as the Vietnam and Turkey strains. As Medicago's technology requires the genetic sequence of a viral strain and not the live influenza virus, vaccines can be manufactured within 4 weeks of obtaining the genetic sequence ofthe pandemic strain. This is in contrast with all current manufacturing technologies which rely on strain adaptation, leading to an additional 4-6 months before vaccine production can be initiated.
About Medicago
Medicago is committed to provide highly effective and affordable vaccines based on proprietary Virus-Like Particle (VLP) and manufacturing technologies. Medicago is developing VLP vaccines to protect against H5N1 pandemic influenza, using a transient expression system which produces recombinant vaccine antigens in non-transgenic plants. This technology has potential to offer advantages of speed and cost over competitive technologies. It could deliver a vaccine for testing in about a month after the identification and reception of genetic sequences from a pandemic strain. This production time frame has the potential to allow vaccination of the population before the first wave of a pandemic strikes and to supply large volumes of vaccine antigens to the world market. Additional information about Medicago is available at www.medicago.com.
Manufacturing in the United States is in trouble. That's bad news not just for the country's economy but for the future of innovation.
Our list of the 50 most innovative companies, including the following:
On Twitter
Become a Fan on Facebook
Subscribe to the Feed
geddy160
4 Comments
Caterpillar cell culture origin flu vaccine
I suggest you might use a better descriptive term for the flu vaccine described as, "Caterpillar Flu Vaccine Delayed".
It is in fact a caterpillar cell-culture origin flu vaccine, and it is prepared using a baculovirus vector containing a DNA copy of the flu virus RNA coding for the hemagglutinin protein.
The point is that it is a cell-culture origin product. Calling it a cell-based vaccine is a poor descriptor.
Reply