ULTRASTRUCTURAL IMMUNOLOCALIZATION OF POLYAMINES IN HELA-CELLS SUBJECTED TO FAST-FREEZING FIXATION AND FREEZE-SUBSTITUTION

Polyamines have been localized at the ultrastructural level in HeLa ce lls subjected first to fast-freezing fixation (FFF)-freeze substitutio n (FS) and then to an immunocytochemical method combining anti-polyami ne antibodies and immunogold labelling. Polyamines were found in both the cytoplasm and the nucleus and, in the latter, particularly over th e dense chromatin area. To our knowledge, this is the first example of the electron microscopic localization of a hapten after FFF-FS. For t he preservation of fine ultrastructural details, this FFF-FS method is not only adequate but also greatly reduces, if not totally eliminates , any leeching-out and redistribution of the polyamines during the pre paration of the sample. For the preservation of antigenicity in situ d uring FS, epoxy resin was more effective than hydrophilic LR white res in, probably due to the solubility of polyamines in the latter.