Human Monoclonal Antibody against Human Lymphocytic Cells

Human monoclonal antibodies may replace human or xenogeneic antisera and mouse monoclonal antibodies for therapeutic applications. The human IgM monoclonal antibody Ha6D3 was produced after in vitro immunization and fusion with a mouse myeloma. Its reactivity against human normal and leukemic cells was investigated in cytotoxicity assays, and the antigen distribution in normal tissues was investigated with biotinylated Ha6D3 and avidin-peroxidase complexes. It was shown that Ha6D3 reacts preferentially with human lymphocytic cells. Only moderate reactions with epithelial cells in some organs were observed in cryostat sections, but because of poor accessibility in vivo these reactions were considered to be negligible.