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A nonprofit in Bethesda is developing a new weapon in the global vaccine arsenal against malaria.

The Malaria Vaccine Initiative, which already funds efforts to develop vaccines to prevent people from contracting the deadly infection, said Friday it is taking a novel tack in its war on malaria. The group is launching a collaboration with the Johns Hopkins Bloomberg School of Public Health in Baltimore and the Sabin Vaccine Institute in Washington, D.C., to produce a new type of vaccine that would break the mosquito-human-mosquito malaria transmission cycle.

The vaccine would be given to both uninfected people and those who have already contracted malaria, said Ashley Birkett, the Bethesda group's director of pre- and early clinical research and development.

The person would then develop antibodies, which, when transmitted to another mosquito through a bite, would prevent this second mosquito from producing in its gut the malaria parasite it would otherwise transmit to another victim through a bite.

"It's taking advantage of the complex life cycle of the parasite in two hosts — the human host and the mosquito host — to block the transmission," Birkett said.

The concept came from Rhoel Dinglasan of Johns Hopkins, he said.

"The idea of a transmission-blocking vaccine is not a new concept ... but most target the parasite," Birkett said. "This is different: Rather than target the parasite, this targets the gut of the mosquito," where the antibodies block uptake of the parasite after a blood meal.

Malaria kills nearly 900,000 people per year, most of them children younger than 5, according to the initiative, which is part of the Program for Appropriate Technology in Health of Seattle. PATH is heavily funded by the Bill & Melinda Gates Foundation.

"The heartbreaking devastation caused by malaria cannot be overstated," said Peter Agre, Nobel laureate and director of the Johns Hopkins Malaria Research Institute, in a statement. "Blocking transmission by novel vaccines may provide the approach needed to stop the epidemic. MVI deserves great credit for supporting potentially exciting research that would otherwise be abandoned due to lack of precedent."

Birkett declined to disclose the finances behind the initiative, as that could "set a level of expectation for other applicants."

"We start most of our new programs with a fairly modest investment," he said. "If they continue to generate positive data, then we go to the next level of investment, into clinical work, where dollar amounts go up quite significantly."

Under the collaboration, the Sabin institute, which is also funded by the Gates foundation, will work to produce large quantities of the antigen, called AnAPN1, which would prompt the body to produce the antibodies needed to disrupt transmission. Manufacture of the vaccine must be low-cost, Birkett said, as entire communities would need to be immunized for the vaccine to work.

Johns Hopkins scientists will then use that antigen in immunization trials on mice, studying its ability to block transmission and any potential side effects of concern. If results, which are expected in mid-2011, are positive, more preclinical tests may be conducted before clinical trials are held.

"The antibodies that we have produced are effective against multiple malaria parasites and, therefore, this antigen may constitute the basis for a future ‘universal' or pan-malaria transmission-blocking vaccine," Dinglasan said in the statement. "This could have a tremendous impact on malaria transmission, even extending beyond those individuals we can reach through a vaccination campaign, since the transmission-blocking component is intended to protect the population as a whole."

The collaboration is part of the Malaria Vaccine Initiative's redesigned research and development strategy, which takes a broader look at malaria vaccine development with the goal of a vaccine that is at least 80 percent effective against clinical disease for more than four years by 2025.

The transmission-blocking concept shouldn't be considered a primary eradication tool, but is a "reasonable" approach that could work well in combination with a vaccine that prevents infection in individuals, says one expert.

Stephen L. Hoffman, CEO of Sanaria, a Rockville company that also receives funding from the Gates foundation and works with the Malaria Vaccine Initiative, said there are "a lot of ifs" in the new approach.

"The concept with that approach — if you could immunize an entire community, if you had a highly effective vaccine — is it could reduce or eliminate transmission," said Hoffman, whose company is developing a vaccine that is designed to prevent the infection of individuals.

"Ours is a whole-parasite approach," Hoffman said. "Theirs is designed to block transmission, but not stop infection. Ours would prevent infection and transmission."

Sanaria is currently testing its candidate in phase 1 trials in Bethesda and Baltimore, and expects results in late spring or summer, he said.

Sanaria is also developing its own version of a transmission-blocking vaccine, Hoffman said, and is seeking funding to support that research. Both types of vaccines, used together, could be "99 percent effective" in wiping out malaria, he said.

A vaccine such as Sanaria's main candidate, by preventing infection in the first place, "could in itself also be a transmission-blocking vaccine," Birkett said.

"It could be the ultimate vaccine, as it would block infection and transmission," Birkett said. "But we don't have that yet."

"Anything that puts money into malaria vaccines is a good thing," Hoffman said. "Nobody knows what the answer is at the end of the day.