A simple technique for supporting single cells in electron microscopic immunocytochemistry and embedding.

Cell suspensions of rat anterior pituitaries were filtered with a polycarbonate filter (pore size 3 micron) and fixed on the filter. After fixation the cells were adherent to the filter and immunocytochemical staining could be accomplished by simply dipping the filter into the different incubation media. The cells could be dehydrated and embedded in Epon 812 on the filter. After polymerization the embedded filter was sawn into small blocks and the cell layer was sectioned tangentially on an ultramicrotome. This method also seems to be applicable to other histochemical studies on single cells.