title: Novel monoclonal antibodies against microcystin and their protective activity for hepatotoxicity.
abstract: Six monoclonal antibodies (MAbs) to microcystin-LR (MCLR), a cyclic heptapeptide hepatotoxin isolated from the cyanobacterium Microcystis aeruginosa, were produced. They showed the protective effects on hepatotoxicity of MCLR in vitro and in vivo, and on the inhibition of protein phosphatase by MCLR. Competitive enzyme-linked immunosorbent assays with various microcystins revealed that the six MAbs recognized a part of the molecule, in particular, a tertial structure around Adda, 3-amino-9-methoxy-2,6,8,-trimethyl-10-phenyldeca-4,6-dienoic acid. The specificity of these MAbs varied slightly. In primary rat hepatocyte cultures, all MAbs showed protective effects against the MCLR-induced cell damages, assessed by morphological changes, lactate dehydrogenase release into the medium, and a calorimetric assay to measure the cell viability using a tetrazolium dye. The M8H5 MAb showing the highest affinity for MCLR blocked the lethal effects and hepatocellular damage to mice. In addition, M8H5 MAb recovered protein phosphatase 2A inhibition by MCLR in a dose-dependent manner, while phosphatase inhibition by okadaic acid was not affected. Thus, the MAbs specifically reacted with the microcystins and prevented their biological activities. This is the first report on the protective effects of specific monoclonal antibodies on MCLR-induced toxicity.
authors.affiliation: Department of Toxicology and Microbial Chemistry, Faculty of Pharmaceutical Sciences, Science University of Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Nagata
authors.forename: H
authors.initials: H
authors.lastname: Soutome
authors.forename: T
authors.initials: T
authors.lastname: Tsutsumi
authors.forename: A
authors.initials: A
authors.lastname: Hasegawa
authors.forename: M
authors.initials: M
authors.lastname: Sekijima
authors.forename: M
authors.initials: M
authors.lastname: Sugamata
authors.forename: K
authors.initials: K
authors.lastname: Harada
authors.forename: M
authors.initials: M
authors.lastname: Suganuma
authors.forename: Y
authors.initials: Y
authors.lastname: Ueno
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology* / Q000378:metabolism; D000918:Antibody Specificity; D001667:Binding, Competitive; D002151:Calorimetry; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D000458:Cyanobacteria / Q000276:immunology / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006825:Hybridomas; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D052998:Microcystins; D010456:Peptides, Cyclic / Q000737:chemistry / Q000276:immunology* / Q000633:toxicity; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors*; D054648:Protein Phosphatase 2; D051381:Rats; D011916:Rats, Inbred F344; D013329:Structure-Activity Relationship
chemical_list: D000911:Antibodies, Monoclonal; D052998:Microcystins; D010456:Peptides, Cyclic; C078588:microcystin; D007770:L-Lactate Dehydrogenase; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2