Phytohemagglutinin-L (PHA-L) consists of only L-type subunits (isolectin L4, "leuko-agglutinin"), and is well suited for high-efficiency induction and the functional analysis of T-lymphocytes. It is highly purified and tested for high-efficiency stimulation of human lymphocytes. It is also used as positive controls for peripheral blood mononuclear cells (PBMC) stimulation.
PHA-L is purified from Phaseolus vulgaris (red kidney bean) by standard chromatographic techniques.
Phytohemagglutinin (PHA), the lectin extract from the red kidney bean, consists of only L-type subunits (isolectin L4, "leuko-agglutinin"). It is an N-acetylgalactosamine/galactose sugar-specific lectin. PHA consists of five isolectins (L4E0, L3E1, L2E2, L1E3, L0E4) each being a tetramer held together by noncovalent forces. The subunits L (leukocyte reactive) have a high affinity for lymphocyte surface receptors, but little for those of erythrocytes, and are responsible for the mitogenic properties of the isolectins. E (erythrocyte reactive) is responsible for the erythrocyte-agglutinating properties.