Well, one way to get proteins, and it was first used in Hepatitis B, is to find patients, find individuals who are already infected with Hepatitis B.

获得蛋白质的方法之一,也是首次用于制造乙型肝炎疫苗的方法,就是寻找患者,寻找到一些已经感染乙肝的患者

耶鲁公开课 - 生物医学工程探索课程节选