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. Colloidal gold can be used to visualize localization of specific saccharide moieties and examine the distribution of plasma membrane glycoproteins based on the binding pattern of Agaricus bisporus Lectin (ABA/ABL) . Colloidal gold labeled ABA/ABL can be viewed via electron microscopy.