A monoclonal antibody reactive with 5-bromo-2-deoxyuridine that does not require DNA denaturation.

We describe a mouse monoclonal antibody (BU-1) reactive with 5-bromo-2-deoxyuridine (BrdUrd). The antibody is different from previously described BrdUrd monoclonal antibodies in that BU-1 does not require pretreatment of cells with strong DNA denaturants in order for the antibody to react with BrdUrd incorporated in the DNA. The antibody can be used in immunocytochemical and indirect immunofluorescent assays and can be used to identify cells that have incorporated BrdUrd. Double staining with BU-1 antibody and propidium iodide has been used to confirm S-phase measurements with the BU-1 antibody. Immunocytochemical stains using the BU-1 antibody do not destroy cell morphology and allow cell identification to be performed simultaneously with S-phase measurements. Flow cytometer two-color fluorescence analysis allows the simultaneous identification of cell surface or cytoplasmic markers and S-phase quantitation. The BU-1 antibody should broaden the application of cell kinetic measurements to individual elements of cell populations that are heterogeneous with respect to morphology, surface marker, and other biological features.