Mitogenic proteins of pokeweed. I. Purification, characterization and mitogenic activity of two proteins from pokeweed (Phytolacca octandra)

Immunology. 1979 Aug;37(4):785-92.


Saline extracts from the roots of the pokeweed species. Phytolacca octandra were separated by ion-exchange chromatography into three fractions, Po-1, Po-2 and Po-3. Po-1 contained two monomeric proteins with molecular weights of 36,000 and 29,000 and these were partially purified by gel filtration. Po-2 was purified as a single polymeric protein composed of approximately ten 14,000 mol. wt polypeptides and is a new pokeweed mitogen. Po-3 was purified as a single polymeric protein composed of approximately four 31,000 mol. wt subunits, and apart from its polymeric structure closely resembles commercial pokeweed mitogen (PWM). Po-2 and Po-3 were mitogenic for unseparated human peripheral blood lymphocytes but the degree of mitogenic activity in Po-2 preparations was dependent on storage following purification. Purified B cells were not stimulated by either mitogen. Po-3 was a potent mitogen for T cells but preparations of Po-2 required storage before they stimulated T cells. Higher responses were observed in co-cultures of B and T cells than in separated B and T cell cultures. It is suggested that human B and T lymphocytes show synergy in their responses to Po-2 and Po-3.

MeSH terms

  • Amino Acids / analysis
  • B-Lymphocytes / immunology
  • Cells, Cultured
  • Dose-Response Relationship, Immunologic
  • Electrophoresis, Polyacrylamide Gel
  • Humans
  • Mitosis / drug effects
  • Molecular Weight
  • Plant Lectins
  • Plants / analysis*
  • Pokeweed Mitogens / isolation & purification*
  • Pokeweed Mitogens / pharmacology
  • T-Lymphocytes / immunology


  • Amino Acids
  • Plant Lectins
  • Pokeweed Mitogens