Two Americans get treated with health-related experimental Ebola virus.
The tobacco plant is better known for its harmful effects, but its specially modified leaves can cultivate a potential treatment for Ebola. ZMapp, grown in these customized leaves, was given to the two Americans infected with the virus in Africa.
BioProcessing of Kentucky was approached by Emory University and Samaritan’s Purse to cultivate a limited amount of ZMapp. Producing the serum is time consuming, as the plants take several weeks to grow before the special protein can be injected into them. It then takes another week for the plants to make enough copies of the protein before they can be harvested and distilled, according to the company’s spokesperson, David Howard.
ZMapp will have to go through the formal drug approval process before it can be used on a wide scale. According to Larry Zeitlin, president of Mapp Biopharmaceuticals, the California based co-developers of the serum, the compound was only developed in January. It was tested on monkeys, but Dr. Kent Brantly and Nancy Writebol were the only humans to whom the treatment has been given.
ZMapp is a combination of three antibodies, which help in two ways: One antibody alerts the immune system to the infected cells, which destroys them, according to Erica Ollman Saphire, an immunology professor at the Scripps Research Institute who has received a government grant to study the antibodies. It is thought that the other two antibodies prevent the virus from making copies of itself. Though there is much to be learned, the serum seems to neutralize the Ebola virus.
However, other researchers who have studied Ebola urge cautious optimism. Thomas Geisbert, professor of infectious disease at the Galveston Medical Branch of the University of Texas, has studied the virus since 1988. He says accounts of Dr. Brantly’s dramatic recovery, in an hour of taking the serum, don’t make sense.
He says that monkeys with Ebola have ‘haemorrhagic fever’ with ruptured blood vessels, and it takes some time for the skin to heal. Other accounts have stated that Dr. Brantly was given blood transplanted from a patient who had recovered from Ebola. Geisbert says that blood could have had some protective elements in it, which is why it’s difficult to say exactly what happened.
Thomas Geisbert’s caution stems from the fact that 40% of the patients from the current outbreak recover without treatment, so it isn’t certain that ZMapp is actually effective in humans. Saphire seems to be relatively upbeat. “It hasn’t been used in humans before, so we didn’t know what would happen,” she says. However, antibodies are beneficial in treating diseases and preserving health.
All monkeys in a given experiment can be saved if treated within 24 hours. If the disease develops over several days, it results in 50% casualties. Saphire says researchers were anxious about the serum working for Dr. Brantly and Writebol because many days had passed before they were treated with the serum.
Saphire expects the first human trials of ZMapp to begin in 2015.