Lectin-induced apoptosis of tumour cells M.Kim1, M.V.Rao1, DJ.Tweardy2, M.Prakash3,

The mechanisms of cytotoxic activity of Griffonia simplici-folia 1-B4 (GSIB4) and wheat germ agglutinin (WGA) lectins against various murine tumour cell lines were studied. Tumour cells that lack lectln-binding carbo-hydrates were resistant to lysis by these lectins. However, YAC-1 cells that expressed GS1B4 Iectin-binding sites showed low sensitivity to rysis. To further analyse the relative importance of cell surface carbohydrates in lectin cytotoxicity, BL6-8 melanoma cells, whkh do not express the al,3 galactosyltransferase (al,3GT) gene and cell surface a-galactosyl epitopes reacting with GS1B4 lectin, were transfected with cDNA encoding al,3GT. After transfection, BL6- & cells expressed high levels of GS1B<-binding a-galactosyl epitopes, but remained resistant to lysis by GSIB4 lectin, suggesting that the presence of Iectin