Erythrin lectins are composed of two distinct subunits of about 28kda and 26kda. Ecl-bound sugar structures are commonly found in membrane and serum glycoproteins of mammalian origin. This structural sialic acid substitute appears to prevent lectins from binding. This specificity provides an opportunity to isolate mammalian glycoproteins using agarose binding ECL. It has been reported that the lectin can be used to isolate human natural killer (NK) cells using negative selection screening techniques. NK cells appear to lack the surface sugar structure needed to bind ECL, and unlike other monocytes, it does not attach to a petri dish coated with ECL. Since this process involves negative selection screening techniques, a high recovery rate of active NK cells can be obtained. Adherent cells can also be recovered by culture in galactose or lactose. Fluorescein-labeled erythritum lectins bind appropriate amounts of fluorescent dyes to provide optimal staining properties for the lectins. This conjugated substance basically does not contain unconjugated fluorescent dyes. The excitation maximum is 495nm and the emission maximum is 515nm.