Disclosed are immunoconjugates having in particular specificity for CD138 expressed on target cells and which display homogenous targeting. The immunoconjugates may be sterially hindered and/or contain a cleavable linker.在此揭露的是對表現在靶細胞上之CD138具有特別專一性之免疫綴合物,其展現均一的靶定性。該免疫綴合物可為立體障礙性的和/或含有可被剪切的連接子。