Immunofluorescence analysis of LAMP-1 expression. Cells were fixed/permeabilized in ethanol before blocking in goat serum, incubating with LAMP-1 MoAb, and then exposing to an FITC second step. Cells were examined by fluorescence microscopy and photographed. Shown are photographs of typical single cells (centered within the frame) from parental U-937 cells (A and B) or U-A10 cells (C and D).