Tobacco-derived ‘plantibodies’ to the rescue
The number of people killed in the West Af­rican ebola outbreak has reached 932 after 45 deaths in three days.
Latest figures from the World Health Organisation (WHO) showed the number of suspected, probable or con­firmed cases rose by 108 in the same period, between August 2 and 4. Most of the new cases were in Liberia.
More than 1,700 people have now been infected or are suspected of being infected since the tropical virus broke out earlier this year. Among the most recent casualties is a Saudi Arabian who died of a heart attack in Jeddah yes­terday.
He had travelled to Sierra Leone on business and had symptoms similar to those found in people suffering from ebola. Meanwhile, a Spanish priest, who contracted the vi­rus while working as a chap­lain at a hospital in Monrovia, has been flown to Madrid for treatment.
He was one of three mis­sionaries quarantined at San Jose de Monrovia Hospital in Liberia who have tested posi­tive. Five more ebola cases have been confirmed in Nige­ria, bringing the total number to seven in the capital, Lagos, where the new patients are being treated in an isolation ward. Two of the victims have died, one a patient who arrived from Liberia, and the other the nurse who treated him.
Officials from the WHO are holding a two-day emergency meeting in Geneva to establish if the virus is a global threat. In the UK, a resident in Wales has decided to stay home in quarantine and was being monitored by health officials following possible exposure to ebola while visiting western Africa.
Meanwhile, Drugmakers’ use of the tobacco plant as a fast and cheap way to produce novel biotechnology treat­ments is gaining global atten­tion because of its role in an experimental Ebola therapy.
The treatment, which had been tested only in lab animals before being given to two American medical workers in Liberia, consists of proteins called monoclonal antibodies that bind to and inactivate the Ebola virus.
The drug so far has only been produced in very small quantities, but interest in it is stoking debate over whether it should be made more widely available to the hundreds of people stricken with Ebola in Africa while it remains un­tested.
“We want to have a huge impact on the Ebola out­break,” Mapp CEO Kevin Whaley said in an interview at company headquarters in San Diego. “We would love to play a bigger role.” Whaley said he was not aware of any significant safety issues with the serum. He would not dis­cuss whether the company has been contacted about provid­ing the drug overseas.
For decades biotech com­panies have produced such antibodies by growing geneti­cally engineered mouse cells in enormous metal bioreac­tors. But in the case of the new Ebola treatment ZMapp, developed by Mapp Pharma­ceuticals, the antibodies were produced in tobacco plants at Kentucky Bioprocessing, a unit of tobacco giant Reynolds American.
The tobacco-plant-pro­duced monoclonals have been dubbed “plantibodies.”
“Tobacco makes for a good vehicle to express the antibod­ies because it is inexpensive and it can produce a lot,” said Erica Ollmann Saphire, a pro­fessor at The Scripps Research Institute and a prominent re­searcher in viral hemorrhagic fever diseases like Ebola. “It is grown in a greenhouse and you can manufacture kilo­grams of the materials. It is much less expensive than cell culture.”
In the standard method of genetic engineering, DNA is slipped into bacteria, and the microbes produce a protein that can be used to combat a disease. A competing approach called molecular “pharming” uses a plant instead of bacte­ria. In the case of the Ebola treatment, Mapp uses the com­mon tobacco plant, Nicotiana benthanmianas.
 

Ebola: Saudi killed as death toll rises to 932