FIG. 1.

Flow cytometric analysis of FN and LM binding to stationary-phase promastigotes (A) and amastigotes (B) of L. amazonensis. Cells (10⁷) were washed in PBS and incubated for 30 min at 25°C with 1, 5, or 10 μg of FN- or LM-FITC (as indicated at the top of the panels), washed thrice, and analyzed by flow cytometry. We observed maximal surface fluorescence with 5 μg or higher, and results using 5 μg are shown. This resulted in a definitive shift in the surface fluorescence of the entire population of cells (compare top panels with those of unlabeled cells in the bottom panels). The specificity of binding was tested by the preincubation of cells with unlabeled proteins (indicated within each group) under the same conditions prior to incubation with FN- or LM-FITC.