Agaricus bisporus agglutinin (ABA) is an affinity-purified tetramer composed of two to four isolectins. ABA has two distinct carbohydrate binding sites, one for galactose-ß-1,3-N-acetylgalactosamine and another for galactose-ß-1,3-N-acetylglucosamine. Agaricus bisporus has an anti-proliferative effect on cancerous cells. ABA can be internalized by clathrin-coated vesicles after binding to surface glycoproteins, thus making ABA an inhibitor of its nuclear import of signal-dependent proteins.
Cy5, when bound to Agaricus bisporus Lectin (ABA/ABL), 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.