Phytohemagglutinin (PHA) is a complex of oligosaccharides (composed of galactose, n-acetylglucosamine and mannose) and proteins, belonging to the macromolecular glycoproteins, it is found in some beans seeds, with activities to promote mitosis and induce interferon secretion. PHA is a tetramer glycoprotein formed by non-covalent bonding of four subunits, containing two subunit molecules, the L subunit (leukocyte lectin) and the E subunit (erythrocyte lectin), so there are five isomers, including L4, L3E1, L2E, L1E3 and E4. Currently, there are several forms of PHA on the market: PHA-L, PHA-E, PHA-M and PHA-P, etc. PHA-L is a purified L4, whose main function is to stimulate T lymphocytes, and is widely used in immunological research. PHA-E is purified E4 and is mainly used in the study of erythrocyte agglutination or glycosylation modification. PHA-P is protein form of PHA, PHA-M is sticky protein form of phytohemagglutinin, which is mainly used to stimulate the proliferation of peripheral mononuclear cells, promote the production of certain cytokines and the expression of membrane surface proteins. This product is lyophilized powder, it was extracted from kidney bean and purified by ion exchange chromatography.