Amgen Inc. is teaming with the Bill & Melinda Gates Foundation to develop a faster production method for Zmapp, an experimental ebola treatment, according to the company. Zmapp, a mixture of antibodies, is being developed by Mapp Biopharmaceutical Inc. in San Diego. It has been used on a handful of patients before the supply ran out in August. Among them were two U.S. health workers who recovered after the treatment and a Spanish priest who died. The drug is made using genetically altered tobacco plants, which is a slow process. Amgen, based in Thousand Oaks, will work with the Gates Foundation, the World Health Organization and the U.K.-based Wellcome Trust to develop a faster production method. Amgen plans to assign 12 to 14 staff members to see if the drug can be made in Chinese hamster ovary cells, said Kristen Davis, an Amgen spokeswoman, in an email to the Business Journal. Using such cells is an established biomedical production technique used for Epogen, an anemia drug that has been a blockbuster for Amgen for decades. “The gravity of the impact of the Ebola outbreak and Amgen’s expertise in developing monoclonal antibodies provide a unique opportunity to assist in the efforts to manage this growing health care concern,” the email said. Shares closed Monday up $3.82, or 2.8 percent, to $137.51 on the Nasdaq.