There has been some concern m recent years that economic interests in the biotechnology area could, particularly through patenting, have a constricting influence on scientific research. Despite this concern, there have been no studies of this phenomenon beyond isolated cases. In this article we examine the evolution of the biomedical field of hybridoma/monoclonal antibody research with detailed examples of the three types of patent claims that have emerged there—basic claims, claims on application techniques, and claims on specific antibodies. We analyze (...) the impact of these claims and their legal histories on the free flow of scientific information and, the activity of scientific researchers. We conclude that such patent claims present severe restrictions for both, not only in the monoclonal area but in general, amounting to a subtle but significant shift in the political economy of science and technology. (shrink)