Just a few years ago IBD researchers were frustrated by the lack of good animal models for their studies. The available models were inadequate because it was unclear how relevant they were to the human diseases. The most important question in IBD is what starts the disease. These animal models frequently depended on initiating factors that obviously bore no relationship to the human diseases. However, the development of new sophisticated molecular biology techniques has changed the picture dramatically.
Scientists are now able to design and breed mice lacking a specific gene.
This allows scientists to ask very specific questions about the importance of various molecules in the functioning of the immune system. By studying the offspring who lack the molecule of interest one can then infer how important the molecule is and what it is needed for. If the knockout mice die before they are born then it is clear that the missing molecule is vital in development for example. A number of expert immunologists have created knockout mice in order to evaluate the role of specific molecules in the function of the immune system. Clearly, when the immune system is altered the sole or predominant manifestation may be in the intestine.