ULBP2-BB4

ULBP2-BB4 is a recombinant bispecific fusion protein engineered to engage and activate natural killer (NK) cells for targeted antitumor immunotherapy. It consists of two domains: ULBP2, which binds the activating NK cell receptor NKG2D, and BB4, an antibody-derived moiety that binds to CD138, a surface antigen overexpressed on multiple myeloma and other tumor cells. By simultaneously engaging NKG2D on NK cells and CD138 on tumor cells, ULBP2-BB4 induces NK cell activation and cytotoxicity against malignant plasma cells, leading to interferon-gamma secretion and enhanced NK-mediated lysis of CD138-positive tumor cells. In preclinical models, ULBP2-BB4 showed potent antitumor activity both in vitro and in vivo, abrogating tumor growth in a mouse model of multiple myeloma when administered with human lymphocytes. The agent is positioned as a novel immunotherapeutic candidate for multiple myeloma and possibly other CD138-expressing malignancies[1][2][7].