Immuno-crossreactivity and toxicity assessment of conjugation products of the cyanobacterial toxin, microcystin-LR

Immunoassays are increasingly used to investigate the production, propertie s and fares of the cyanobacterial hepatotoxic microcystins in vitro and in vivo. Responses of an ELISA immunoassay to microcystins have been determine d using the authentic toxin antigen, microcystin-LR, and conjugation produc ts between the toxin and glutathione, cysteine-glycine and cysteine. The an tibodies against microcystin-LR crossreacted with the toxin conjugation pro ducts with similar affinities (96-112%) to that of microcystin-LR, when ass ayed at a concentration of 1 mu g l(-1). Toxicity assessment of the conjuga tes, in comparison to microcystin-LR, indicated a reduction according to mo use bioassay. In vitro protein phosphatase inhibition assay indicated that the conjugates possessed approximately 3-9-fold lower toxicity than microcy stin-LR. (C) 2000 Federation of European Microbiological Societies. Publish ed by Elsevier Science B.V. All rights reserved.