Contact: Alexander Shtifman
Phone: 617-713-8989
alex...@childrens.harvard.edu

Senior Investigator Klaus Rajewsky, M.D., and colleagues recently published an important new discovery regarding microRNA's key role in regulating the immune response, in an April 2007 issue of Science magazine.

Rajewsky's group found that a particular microRNA known as miR-155 appears to be instrumental in regulating the entire immune system, specifically in determining T helper cell differentiation and the germinal center reaction that produces optimal T cell-dependent antibody responses. This is the first time that microRNA-snippets of RNA which exert biological control at multiple levels-has been shown to be a significant player in the course of immune responses.

Interestingly, the bic gene that produces miRNA-155 has been shown to be highly expressed in a variety of B cell lymphomas, including in Hodgkin-Reed-Sternberg cells in Hodgkin's disease.

According to Rajewsky, in an April 27th article in the New York Times, this discovery about microRNA and the immune system was "a completely new development" that is "leading to a lot of rethinking" in the field of immunology. Conceivably, new therapies for a range of diseases could be made from drugs that inhibit the operation of types of microRNA which influence different cells crucial to disease processes.

IDI researcher To-Ha Thai, in the Rajewsky lab, served as first author on the Science paper. She was joined by co-authors from IDI, the FIRC Institute for Molecular Oncology in Italy, Brigham & Women's Hospital in Boston, and the Max Delbruck Center for Molecular Medicine in Germany.

Rajewsky, who recently became the first incumbent of the Fred S. Rosen Chair of Pediatrics at the IDI, was also contacted about this discovery by RNAi News (which ran an extended interview with him) and National Public Radio of Poland.