Imaging of the lectin-labeled cell surface of human lymphocytes by the useof atomic force microscope

The atomic force microscope (AFM) is a new useful tool to examine the surfa ce structure of specimens with a higher resolution than the conventional sc anning electron microscope. In the present study, we used the AFM to observ e the surface of paraformaldehyde-fixed human lymphocytes processed for his tochemistry using a biotinylated lectin, wheat germ agglutinin, followed by colloidal gold and silver-enhancement method. Before the treatment, no par ticles were attached to the cell surface. After treatment, many particles a bout 100 to 150 nm in diameter were visualized on it. Since we could observ e the same cells on the slide glass before and after treatment, the AFM has the advantage to enable us the repeated imaging of samples treated with va rious kinds of histochemistries.