Phaseolus vulgaris lectin (PHA E+L, also known as PHA P, P standing for phytohemagglutinin) is isolated from red kidney beans. It consists of two isolectins PHA-E and PHA-L, erythroagglutinin and leucoagglutinin, of which both possess strong mitogenic activity. PHA P has a molecular weight of 126 kDa and an isoelectric point between pH 5.2 and pH 6.2. It has a carbohydrate specificity for complex oligosaccharides and elutes with bovine thyroglobulin or acetic acid. This lectin agglutinates blood group A (-SA).

PHA P can be used for mitogenic stimulation to human lymphocytes. It has the potential to induce closer contacts between adjacent cell membranes and has been successfully used for membrane-induced fusion in human oocytes, bovine oocytes, and caprine oocytes. Phytohemagglutinin was direct evidence for the involvement of bacterial lectins in the initiation of infection, the basis for present attempts in academia and industry to apply carbohydrates for anti-adhesion therapy of such diseases.