In situ immunocytochemical staining method for haemopoietic cells grown in vitro

Characterization and enumeration of haemopoietic cells grown in vitro is routinely performed either on unstained cultures or on cultures stained by cytochemical agents. This report describes a novel method for the immunocytochemical analysis of cells grown in plasma clots. The stain is performed in situ by subjecting the whole plasma clot in the culture dish to the staining procedure. The growth of early haemopoietic progenitor cells was monitored in cultures from normal human peripheral blood and proliferating progenitor cells were identified with an anti-human transferrin receptor monoclonal antibody followed by a two-layer immunoperoxidase stain. The number of transferrin receptor positive clusters demonstrable after 5 days of culture was similar to the number of haemopoietic colonies detectable after 12 days of culture.