Tomato lectin, although sharing some specificities with potato lectin, Datura lectin, and wheat germ agglutinin, has been reported to be dissimilar in many respects. LEL binds well to glycophorin and Tamm-Horsfall glycoprotein and has been used effectively to label vascular endothelium in rodents. Fluorescein labeled Tomato lectin has an appropriate number of fluorochromes bound to provide the optimum staining characteristics for this lectin. This conjugate is supplied essentially free of unconjugated fluorochromes. The excitation maximum is at 495 nm and the emission maximum is at 515 nm.