Affinity purified Wisteria floribunda agglutinin or lectin (WFA/WFL) is composed of four subunits. This lectin is not blood group specific although it does react stronger with human type A1 cells over A2, B, or O cells. The presence of a sialic acid residue may cause a lack of WFA reactivity. WFA contains a strong hemagglutinin activity and is a potent mitogen, both strongly inhibited by GalNAc, although mitogenic activity is also inhibited by N,Nâ€™-diacetylchitobiose.Cy5, when bound to Wisteria floribunda Lectin (WFA/WFL), can show the binding pattern of this lectin in cellular imaging and flow cytometry. The excitation wavelength required for Cy5 to fluoresce is high enough to avoid overlap with most other fluorochromes, making it useful for dual-labeling experiments. Because of this high excitation, there is typically less background from autofluorescence of biological specimens.