PC10 monoclonal antibody to proliferating cell nuclear antigen as probe for cycling cell detection in developing tissues. A combined immunocytochemical and flow cytometric study.

Proliferating cell nuclear antigen (PCNA), also referred to as cyclin, is an auxiliary protein to DNA-polymerase delta and a proposed marker of replicating cells. We have investigated the applicability and limitations of PC10 monoclonal antibody to PCNA in a cell kinetics study of developing human and rat tissues by immunocytochemical and flow cytometric techniques. Our data demonstrate that the epitope recognized by PC10 antibody is resistant to wax embedding, but sensitive to aldehyde fixation; conversely, alcoholic fixative solutions preserve the immunoreactivity to PC10. Tissue distribution, DNA content and bromodeoxyuridine uptake confirm that PC10-immunoreactive cells in alcohol-fixed tissues are cycling (G1-, S- and G2-phases traversing) cells. It is concluded that the PC10 antibody can be regarded as a powerful tool to study cell kinetics and differentiation in developing tissues, provided that the tissue processing is adequate.