The immunosuppressive effect of Doxorubicin (DXR) has been circumvented so that monoclonal antibodies (MAbs) reacting with DXR and other anthracycline derivatives have been obtained. The MAb described here (MAD11) belongs to the IgG2 class and selectively recognizes epitopes located at or near the aromatic ring D of the anthracycline molecule. MAD11 differs from another MAb (MAD2) obtained from the same somatic hybridization and previously described which preferentially reacts with aliphatic ring A of anthracycline.