New monoclonal antibody specific for a 6.5 kDa glycoprotein which presentsmainly on a B cell of chronic lymphocytic leukemia (CLL)

Chronic lymphocytic leukaemia (CLL) is a most common form of adult leukemia . No specific marker for CLL has been defined until today. We attempt to pr oduce a specific monoclonal antibody (mAb) to CLL B cells. For this purpose , Balb-C mice were immunised with peripheral blood lymphocytes of a patient with CLL. After the fusion, the immunised mouse spleen cells and SP2/0 mye loma cell line, antibody secreting clones were selected by ELISA and specif ic antibody was determined by flow cytometry. Leukemic cells from different patients, different cell line and lymphoid tissue were tested with this mA b using how cytometry and immunoperoxidase methods. Ligand of the mAb on ce ll surface was identified using epitope analysing method. We have shown tha t this mAb is specific to a molecule with 6.5 kDa molecular weight, which i s present mainly on B CLL cells (63.7 +/- 16.4%). It has also been shown th at this molecule was a glycoprotein. Amongst the different cell lines that were tested, Raji cell, Molt-3 and P3HR-1 cells were expressing this molecu le. We, therefore, suggest that it is a novel molecule with unknown functio n and is mainly present on the B cells of CLL. (C) 2001 Elsevier Science B. V. All rights reserved.