Fig. 6. Immunofluorescence labeling of late endosome/lysosome `markers' associated with parasite-containing organelles at different time points after infection of IFN--treated macrophages with L. amazonensis metacyclic promastigotes. Macrophages were processed for fluorescence microscopy 10 minutes (A), 30 minutes (B-D), 2 hours (E) or 18 hours (F) after the addition of the parasites. Cell preparations were incubated with immune sera or Abs directed against rab7p (A), macrosialin (B), lamp-1 (C,E), cathepsin B (D,F) and then with adequate fluorescein conjugates (green staining). Except in B, macrophage nuclei and parasite nuclei and kinetoplasts were stained with propidium iodide (red staining). In B, the parasites are indicated by arrows. Sections (0.3-0.5 µm thickness) obtained by confocal microscopy are shown. The micrographs are representative of three to eight experiments. Bars, 2 µm.