The H1N1 virus's rapid spread worldwide last year exposed the weaknesses in the global system for swiftly developing, manufacturing and distributing vaccines for newly identified strains of influenza. In Texas, researchers are attacking the first two of these problems through Project GreenVax, which will use a plant-based approach to vaccine development and a modular manufacturing environment that can scale quickly as vaccine demand grows.

Project GreenVax is led by the Texas Plant-Expressed Vaccine Consortium, a joint venture of The Texas A&M University System and pharmaceutical facility technology maker G-Con, LLC, both located in College Station, Texas. The consortium is investing $21 million in GreenVax to go along with the $40 million in funding from the Defense Advanced Research Projects Agency (DARPA).

In the course of just seven months last year the spread of H1N1 influenza worsened from an outbreak specific to Mexico and the United States to a global pandemic and U.S. national emergency. The World Health Organization (WHO) reported that, by the end of the year, H1N1 was responsible for more than 12,200 deaths and had turned up in 208 countries. Although the first cases were reported in April, the first vaccine doses did not start shipping until October.

The WHO's Strategic Advisory Group of Experts (SAGE) on immunization projected in October that it would take the world's labs 12 months to produce about three billion doses of H1N1 vaccine. GreenVax's initial test run is expected to produce 10 million doses of H1N1 vaccine in 12 months using tobacco plants to develop the antibodies. If successful, the researchers say their facility alone could be scaled up to produce 100 million vaccine doses per month.

Breaking a few eggs
Most of the H1N1 vaccines were produced using chicken eggs. Scientists crack the shell and inject the influenza virus into the fluid surrounding the embryo. Ideally, the embryo is infected and the virus multiplies. After several days of incubation the eggs are opened and the virus is removed, purified and used to make the vaccine. It takes about two weeks to produce a flu vaccine using an egg, and the yield is not very high. In order to produce 300 million doses of a vaccine, egg-based production would require some 900 million eggs, according to the U.S. Department of Health and Human Services.

In the plant-based approach, scientists instead infect a plant's leaves with a virus and then grind them up and separate out the antigens produced. Plants offer several potential advantages, says Ted Ross, an associate professor of microbiology and molecular genetics at the University of Pittsburgh's Center for Vaccine Research (CVR). They can be grown quickly and cheaply and have the potential to produce more vaccine per plant than is possible per egg, he says. Still, despite more than a decade of experimentation, he adds, "I don't know of any approved vaccines made using the plant-based approach."

Plants can be very good biofactories, says B. Brett Finlay, a biochemistry and molecular biology professor at the University of British Columbia in Vancouver. However, one problem is that proteins cultivated in plants might be different than those cultivated in animal cells (or a chicken embryo) and not necessarily effective in humans, he adds. "Also, standard FDA rules for plant product use in humans are not as well worked out."

Facilitating the plan
To support its work, GreenVax will begin construction next week on a new 13,500 square-meter biotherapeutic production facility. The facility is essentially a "tilt-wall" warehouse—built using precast concrete walls—that can be constructed in eight weeks, says Brett Giroir, vice chancellor for research for the A&M System and executive director of the university's Institute for Innovative Therapeutics (IIT).

Built on a 8.5-hectare site on the Texas A&M Health Science Center campus in Bryan, Texas, the facility will house a number of mobile, self-contained podlike laboratories for research as well as room to grow tobacco plants using hydroponics, a method that relies on liquid nutrient solutions. Giroir says that the building will likely contain nine pods, which are essentially modular clean rooms that come with their own filtration systems, computers and wiring. The pods come in different sizes, but the standard size is about 13 meters long and 5.5 meters wide and weighing 15 tons.

Advanced development of laboratory technology is central to GreenVax's mission, Giroir says. "What we've tried to do is in the past year of study and design is to try to design a facility that could be [built] at a fraction of the cost and time and be flexible so it can make multiple products at the same time."

Although G-Con's  prefabricated modules are neither as roomy nor as customizable as a laboratory built from scratch with a particular research group's specifications in mind, the pods would allow vaccine makers to hit the ground running when they are under tight deadlines. The pods are also designed to give researchers some flexibility when configuring their facilities. Each of the mini labs features underlying air bearings. When air is pumped into the bearings, the entire pod will glide over a facility's floor like an air-hockey puck, allowing researchers to move their lab spaces around with little more than a push or pull (see video).

This proposed combination of plants and mobile labs to make vaccines has a lot of potential, according to Ross. "Plants are nice because they are easier [than eggs or chickens] to move to places where vaccines need to be made," he says. It would be easier and less expensive to establish a modular laboratory near the site of an outbreak and make a vaccine there than to make the vaccine in a remote production plant and then transport fragile vaccine vials, he adds.

License to create
The GreenVax project is licensing iBio, Inc.'s iBioLaunch plant-based vaccine manufacturing technology, which the Newark, Del., biopharmaceutical company developed at Fraunhofer USA Center for Molecular Biotechnology in Wilmington, Del. DARPA awarded a team led by iBio and Fraunhofer $12 million a year ago for the second phase of its project to develop biological expression technology that could be used to quickly produce safe and effective vaccines against rapidly emerging health threats. Phase 2's goal is to demonstrate the capability to generate three million doses of vaccine within 12 weeks of an outbreak at a low cost. GreenVax obviously seeks to scale iBio's technology to meet its goal of 100 million doses per month.

Pending a successful demonstration at the end of GreenVax's 12-month trial period, including two validation runs to prove that consistent vaccines can be produced, Texas A&M and G-Con may form their own pharmaceutical company to put these technologies and methods into practice.