title: Toxicity and cytotoxicity of nigrin b, a two-chain ribosome-inactivating protein from Sambucus nigra: comparison with ricin.
abstract: Nigrin b, a lectin isolated from the bark of elderberry (Sambucus nigra L.), has structure and enzymatic activity similar to that of ricin and other type 2 ribosome inactivating proteins (RIPs), and yet is much less toxic to cells and animals. In an attempt to explain this difference, we studied (1) the cytotoxicity of both lectins at 18 and 37 degrees C, and in the presence of substances interfering with intracellular routing, and (2) the binding of nigrin b to, and its uptake and degradation by HeLa cells, in parallel with ricin. As compared with the latter, (1) less nigrin b was bound and more was degraded by cells, with a resulting lower concentration remaining inside the cells, and (2) there is evidence for a different intracellular routing followed by the two lectins. These results may explain at least partly the different cytotoxicity and consequently the lower toxicity to mice of nigrin b compared with ricin.
authors.affiliation: Dipartimento di Patologia Sperimentale, Bologna, Italy.
authors.forename: M G
authors.initials: MG
authors.lastname: Battelli
authors.forename: L
authors.initials: L
authors.lastname: Citores
authors.forename: L
authors.initials: L
authors.lastname: Buonamici
authors.forename: J M
authors.initials: JM
authors.lastname: Ferreras
authors.forename: F M
authors.initials: FM
authors.lastname: de Benito
authors.forename: F
authors.initials: F
authors.lastname: Stirpe
authors.forename: T
authors.initials: T
authors.lastname: Girbés
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001667:Binding, Competitive; D006367:HeLa Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007928:Lethal Dose 50; D051379:Mice; D009699:N-Glycosyl Hydrolases / Q000302:isolation & purification / Q000378:metabolism / Q000633:toxicity*; D037121:Plant Lectins; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism / Q000633:toxicity*; D014176:Protein Biosynthesis; D054788:Ribosome Inactivating Proteins / Q000302:isolation & purification / Q000378:metabolism / Q000633:toxicity*; D054790:Ribosome Inactivating Proteins, Type 2; D012276:Ricin / Q000378:metabolism / Q000633:toxicity*; D013696:Temperature; D014197:Trees
chemical_list: D037121:Plant Lectins; D010940:Plant Proteins; D054790:Ribosome Inactivating Proteins, Type 2; C579416:nigrin b protein, Sambucus nigra; D012276:Ricin; D009699:N-Glycosyl Hydrolases; D054788:Ribosome Inactivating Proteins