Plant lectins as inhibitors of tumour growth and modulators of host immune response.

The antitumour activities of four plant lectins, phytohaemagglutinin, pokeweed mitogen, soybean agglutinin, and wheat germ agglutinin, were evaluated on a murine ascitic lymphoma. The effects of lectin treatment on mitogenic response of peripheral blood lymphocytes and macrophage-mediated tumour cell lysis were also assessed. All four lectins studied were found to be able to restrict tumour growth and to improve the life expectancy of the host. The response of peripheral blood lymphocytes towards mitogenic stimulation was found to be improved and enhancement of tumour cytolysis by peritoneal macrophages was noted following lectin treatment.