Coming Soon: Made-to-Order Human Antibodies （为人类自己量身定做的抗体）_生物论文

　　经过20年的艰苦工作，科学工作者们已经找到一种带有魔力的“子弹”，它可以从所有的细胞中把那些已经癌变的或者被病毒感染的细胞挑出来，并把他们杀死。这种具有非凡“火力”的免疫系统蛋白质就是抗体。现在，一种起源于人正常或癌变的白血细胞的新细胞系可以在试管中制造这种抗体。

　　为了抵抗病毒，癌细胞和其他的危险物质，免疫系统又从抗体生产细胞——B细胞的固定队列中“创建”了一支新“劲旅”。每支“劲旅”都装备有一种特殊的抗体，这种抗体能够识别入侵者，并能粘到入侵者身体的某一特殊点上。正常情况下，曾经受过感染人和动物，其血液中会被各种抗体所充斥。在1975年，科学工作者造出了一种叫杂交瘤的小鼠细胞系，它可以产生一种抗体，这种抗体可以作为识别细胞内蛋白质的一种有用的工具。这种所谓的单克隆抗体也有助于医生设计新的诊断方法。但有一点需要说明，小鼠的抗体不能搜寻、杀死人体中的入侵者，因为人体会把这些抗体看作是外来物质加以抵抗。

　　令人兴奋的是，剑桥大学的免疫学家Abraham Karpas和他的伙伴们经过20多年的努力工作，终于找到了一条改造人体细胞的方法，经过改造的这种人体细胞可以专门用来研究人类自己的单克隆抗体。制造小鼠的杂交瘤还有一个很难解决的问题：从免疫过的细胞脾脏中取到的B细胞，它在培养器皿中会逐渐死亡，如果一种叫骨髓瘤的白血细胞就保险得多。Karpas说，人的骨髓瘤细胞却“不能做到这一点”。这个研究小组花了很多年的时间才让人的骨髓瘤细胞在培养器皿中快速生长，并挑选出那些能在适当条件下存活的细胞。

　　2月13日，国家科学研究所的一份研究进展报告中说：这种骨髓瘤细胞系可以转化出九种不同的人类杂交瘤，每种杂交瘤能生产一种特殊的抗体，其中包括抵抗HIV病毒的抗体。Karpas说：这项技术可以帮助有关的研究人员用肿瘤组织中的B细胞来制造抗癌的抗体，用艾滋病病人的B细胞制造能搜寻、杀死HIV病毒的抗体。

　　Fox Chase癌症研究中心的免疫学家Gregory Adams说：“这是一项重大的发展，，这种全新的细胞系可以使人抗体的生产变得更容易、更廉价，特别是用在疾病治疗方面”。另一位免疫学家Paul Nelson也说：“这项技术是非常令人兴奋和鼓舞的。”

原文：

　　After 20 years of painstaking work, researchers have found a way to a kind of magic bullet to seek out and destroy cancer cells and cells infected with viruses such as HIV. The ammunition--immune system proteins known as antibodies--can be made in a test tube by a new cell line derived from normal and cancerous human white blood cells.

　　To ward off viruses, cancer cells, and other menaces, the immune system drafts a few brigades from a huge standing army of antibody-producing cells called B cells. Each brigade pumps out a unique antibody that recognizes and binds to a particular spot on the invader. Normally, blood from an infected person or nimal will be loaded with various antibodies. But in 1975, researchers made mouse cell lines called hybridomas that enerate a single type of antibody--a useful tool for identifying ellular roteins. These so-called monoclonal antibodies also helped physicians devise new diagnostic tests. But the mouse antibodies wouldn't seek and destroy invaders in humans, because the immune system often rejected them as foreign.

　　Intrigued, immunologist Abraham Karpas of Cambridge University and his colleagues worked for more than 20 years to find a way to make human cells specialize in monoclonal antibodies. Even making a mouse hybridoma is tricky: B cells from the spleen of an immunized mouse, which normally died out in culture dishes, must be fused with cancerous white blood cells called myelomas. But the human myeloma cells "wouldn't behave," Karpas says. The team spent years coaxing the cells to grow quickly in culture dishes and teasing out cells that could survive under the right conditions.

　　The resulting myeloma line enabled them to make nine different human hybridomas, each specializing in a particular antibody, including one that latches onto a key protein from HIV, the researchers report in the 13 February Proceedings of the National Academy of Sciences. The technique could now help researchers use B cells from tumor tissue to make anticancer antibodies, and B cells from HIV survivors to make antibodies that seek out and destroy the virus, Karpas says.

　　"It's an important development," says immunologist Gregory Adams of the Fox Chase Cancer Center in Philadelphia. The new cells will make it easier and cheaper to develop human antibodies, particularly for therapy, says immunologist Paul Nelson of the University of Wolverhampton, United Kingdom. "I think it's quite exciting," he says.