During the last years it has become increasingly clear that production of most cytokines is
not confined to one cell type. Thus, a method to detect cytokines at the single cell level
would be a helpful tool to study the contribution of different cells to cytokine production in
heterogeneous cell populations. Recently, Sander et al.(1991) demonstrated that it is
possible to detect intracellular cytokines by fixation with paraformaldehyde, permeabilization
with saponin and subsequent indirect immunofluorescent staining using fluorescence …