A team at the Graduate School of Medicine, Osaka University, has found that integrin β7 with an active structure is highly expressed specifically in multiple myeloma. Out of over 10,000 monoclonal antibodies that bound to myeloma cells, they identified MMG 49, an antibody that binds to myeloma cells but not to normal blood cells. The protein to which MMG49 binds is integrin β7. MMG 49 did not bind to normal blood cells, even though normal blood cells also express integrin β7 protein, because integrin β7 exists in an inactive structure in most normal blood cells, whereas in myeloma cells many integrin β7
occur constantly in an activated structure. Therefore, CAR-T cells with the antigen recognition site of MMG 49 were prepared. In experiments using mice, it was shown that CAR-T cells derived from MMG49 specifically eliminated myeloma cells without damaging normal cells.
AMED news release, Nov. 7, 2017