A method and apparatus for preparing biological cell samples for
intracellular analysis. The invention is based upon the recognition that
many of the steps of the conventional methods for such sample preparation
can be eliminated, leading to a process that readily lends itself to
automation and the advantages associated therewith. The method of the
invention comprises the steps of (a) cell-fixation, (b) permeabilization
and (c) staining (or labeling) of intracellular molecules of interest by
probes that are readily detectable by flow cytometric techniques, all
without any intervening cell-washing (and re-suspension) steps. Rather,
the single cell-washing step is effected after these three steps have
been carried out. Preferably, the washing step is carried out by passing
the fixed, permeabilized and stained cell sample through a semi-permeable
membrane that serves to filter out (by transmission) interferants to
waste while retaining the cells of interest.
