Antibodies to Proliferating Cell Nuclear Antigen As S-phase Probes in Flow Cytometric Cell Cycle Analysis

The usefulness of different anti-proliferating cell nuclear antigen monoclonal antibodies as S-phase probes in flow cytometric analysis was evaluated after various fixation procedures on human cell lines. With a newly developed detergent extraction/fixation method the monoclonal antibody PC10 acted as a selective S-phase marker. A total of 27 human hematopoietic tumors were analyzed using PC10, and all exhibited the characteristic S-phase recognition pattern. The percentage of PC10-positive cells was easily calculated and showed strong correlation to the fraction of S-phase cells determined from DNA histograms. Using alternative fixation procedures PC10, on the other hand, could recognize all actively cycling cells, a feature also observed for the monoclonal antibodies, 19A2 and TOB7.