Lectin from Phaseolus vulgaris (red kidney bean)

Phytohemagglutinin (PHA) derived from Phaseolus vulgaris is a tetrameric glycoprotein. It consists of two different subunits, that weighs 120 kDa.

Lectin from Phaseolus vulgaris (red kidney bean) has been used:

• as a positive control in ELISPOT (enzyme-linked immunospot) assay
• to induce Th2 polarization for T-cell differentiation in vitro
• as controls in the lymphocyte proliferation assays

PHA consists of two molecular species, an erythroagglutinin (PHA-E) which has low mitogenic activity and high erythroagglutinin activity, and leucoagglutinin (PHA-L) which has high mitogenic and leucoagglutinating activity, but very low erythroagglutinating activity.
PHA-E is not blood group specific, but agglutination can be inhibited by certain oligosaccharides. PHA-P is the protein form of PHA prior to separation and purification of erythroagglutinin and leucoagglutinin. PHA-M is the mucoprotein form. Conjugates are prepared from the corresponding purified lectins.

Purified by a modification of the method of Leavitt.

Agglutination activity is expressed in μg/ml and is determined from serial dilutions of a 1 mg/ml solution. This activity is the lowest concentration to agglutinate a suspension of either human erythrocytes (2% in phosphate buffered saline, pH 6.8) or human leukocytes (10⁷ per mL in saline) after 1 hr incubation at 25 °C.