The present invention provides isolated antibodies (e.g., humanized or human antibodies) that bind to the membrane-proximal domain (MP) of human Melanoma-Associated Chondroitin Sulphate Proteoglycan (MCSP), and are capable of mediating cytolysis of a cell expressing MCSP in the presence of human effector cells or complement. Methods of using such antibodies to induce cytolysis (e.g., ADCC or CDCC) of cells expressing MP-MCSP are also provided.