Michel Nussenzweig's research is focused on understanding the development and function of antibody-producing B lymphocytes. The function of the immune system is to protect vertebrates from pathogens. To accomplish this task, the immune system has developed two types of responses, innate and adaptive. Innate immune responses depend on a series of pattern recognition receptors that have evolved to recognize a restricted set of frequently encountered pathogens. In contrast, adaptive immune responses display a much broader range of diversity and show immunologic memory.
Lymphocytes are the primary effectors of adaptive immune responses.
The advantage of random gene segment rearrangement is that it enables the production of a very large number of distinct receptors that are able to recognize almost any antigen. Our laboratory has focused on understanding the regulation of the development and the function of antibody-producing B lymphocytes. RAG-catalyzed DNA cleavage proceeds by a mechanism that appears to be closely related to catalysis by transposases. We have shown that RAGs are most closely related to bacterial Tn10 transposase. Like Tn10, RAG nicks target DNA and produces hairpins by transesterification, which are then opened in a second nicking reaction.