A chimeric monoclonal antibody directed against human CD20, with potential antineoplastic activity. Anti-CD20 monoclonal antibody SCT400 binds to the B cell-specific cell surface antigen CD20, which triggers an immune response against CD20-positive B-cells, leading to apoptosis. CD20, a non-glycosylated cell surface phosphoprotein, is exclusively expressed on B-cells during most stages of B-cell development and is often overexpressed in B-cell malignancies.