BIRMA-K3, a new monoclonal antibody for CD34 immunophenotyping and stem and progenitor cell assay

A murine monoclonal antibody with specificity for the CD34 antigen has been produced and designated BIRMA-K3. The antibody characterized as IgG1(kappa) has been shown to react with KG-1a cells following treatment of the cells with glycoprotease enzyme, indicating reactivity with the class III epitope of CD34. It was possible to show that class I and class II anti-CD34 antibodies were not able to inhibit binding of BIRMA-K3. Investigation of FITC-labeled as well as PE-labeled BIRMA-K3 resulted in a clear cut-off staining of acute leukemias and CD34+ cell counts in patients submitted to high-dose chemotherapy and stem cell transplantation. The results obtained correlate strongly with those from HPCA-2, the Becton-Dickinson class III antibody.