Co-localization of an endocytic marker and acid phosphatase in a tubular/reticular compartment in macrophages.

Cultured resident murine macrophages are incubated in the continuous presence of the fluorescent endocytic marker Lucifer Yellow and a phorbol ester that activates protein kinase C. Under these steady-state labeling conditions the fluorescent tracer was, for the most part, in a tubular/reticular compartment. Enzyme cytochemical localization of acid phosphatase in the same cells showed essentially a one-to-one correlation between the Lucifer Yellow- and acid phosphatase-containing compartments. Procedures for epifluorescence observation and subsequent enzyme cytochemical examination of the same whole mount cells are described. In addition, chemical fixation methods for the preservation of this labile tubular/reticular compartment are presented.