A humanized monoclonal antibody directed against the human CS1 (CD2 subset 1, CRACC, SLAMF7) antigen with potential antineoplastic activity. Anti-CS1 monoclonal antibody HuLuc63 binds to the CS1 antigen, which may trigger antibody-dependent cellular cytotoxicity (ADCC) in cells expressing CS1. CS1 is a cell surface glycoprotein belonging to the CD2 subset of the immunoglobulin superfamily (IgSF) and is highly expressed by multiple myeloma cells, but minimally expressed by normal cells.