Mistletoe lectin dissociates into catalytic and binding subunits before translocation across the membrane to the cytoplasm.
Hybridomas producing monoclonal antibodies (mAbs) against the mistletoe lectin A-chain (MLA) were obtained to investigate the intracellular routing and translocation of ribosome-inactivating proteins. Anti-MLA mAb MNA5 did not bind the holotoxin but interacted with isolated MLA. This epitope was not recognized upon MLA denaturation or conjugation of MLA with the ricin binding subunit (RTB). Furthermore, the mAbs did not appreciably react with a panel of MLA synthetic octapeptides linked to the surface of polyethylene pins. A study of the cytotoxicity of mistletoe lectin, ricin, and chimeric toxin MLA/RTB for the hybridomas revealed that interchain disulfide bond reduction and subunit dissociation are required for cytotoxic activity of mistletoe lectin.
Agapov
I I
II
State Research Center GNIIgenetika, Moscow, Russia.
Tonevitsky
A G
AG
Moysenovich
M M
MM
Maluchenko
N V
NV
Weyhenmeyer
R
R
Kirpichnikov
M P
MP
D000818:Animals; D000911:Antibodies, Monoclonal; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000032:analysis; D006825:Hybridomas / Q000187:drug effects; D037102:Lectins / Q000737:chemistry / Q000633:toxicity; D046911:Macromolecular Substances; D051379:Mice; D008807:Mice, Inbred BALB C; D014784:Mistletoe; D037121:Plant Lectins; D028321:Plant Preparations; D010940:Plant Proteins; D010946:Plants, Medicinal; D010954:Plasmacytoma; D011993:Recombinant Fusion Proteins / Q000633:toxicity; D054790:Ribosome Inactivating Proteins, Type 2; D012276:Ricin / Q000633:toxicity; D013154:Spleen / Q000276:immunology; D014118:Toxins, Biological / Q000737:chemistry* / Q000276:immunology / Q000633:toxicity*; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000939:Epitopes; D037102:Lectins; D046911:Macromolecular Substances; D037121:Plant Lectins; D028321:Plant Preparations; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D014118:Toxins, Biological; C009674:ribosome inactivating protein, Viscum; D012276:Ricin