Expression of proliferating cell nuclear antigen (PCNA) and Ki-67 antigen in human malignant hematopoietic cells

Human hematopoietic cell lines and fresh lymphoma cells were investigated for their expression of proliferating cell nuclear antigen (PCNA) and Ki-67 antigen using flow cytometry. Ki-67 was detected with a monoclonal antibody and the PCNA content was determined using a human auto-antiserum and in some cases a monoclonal antibody (PC10). The autoantibody to PCNA was found to recognize S-phase cells and the number of positively stained cells was significantly correlated with the S-phase fraction determined from DNA-histograms. There was also a strong association between Ki-67 positivity and the fraction of S-phase cells. By dual parameter analysis of Ki-67 and PCNA detected by the autoantibody a detailed cell cycle analysis could be performed of the lymphoma samples. The recently described PC10 monoclonal antibody was found by FCM to be a good proliferation marker recognizing cycling cells after methanol and detergent treatment, however without any specific cell cycle phase preference.